1984-1994 Yamaha 2hp 2-stroke Outboard Repair Manual

NOTICE This manual has been written by the Yamaha Motor Company primarily for use by Yamaha dealers and their qualified mechanics. It is not possible to put an entire mechanic's education into one manual, so it is assumed that persons using this manual to perform maintenance and repairs on Yamaha outboard motors have a basic-understanding of the mechanical concepts and procedures inherent to outboard motor repair technology. Without such knowledge, attempted repairs or service to this model may render it unfit for use and/or unsafe.

Yamaha Motor Company, Ltd. is continually striving to improve all models manufactured by Yamaha. Modifications and significant changes in specifications or procedures will be forwarded to all Authorized Yamaha dealers and will, where applicable, appear in future editions of this manual.

Particularly important information is distinguished in this manual by the following notations:

NOTE: A NOTE provides key information to make procedures easier or clearer.

A CAUTION indicates special procedures that must be followed to avoid damage to the outboard motor.

WARNING: A WARNING indicates special procedures that must be followed to avoid injury to an outboard motor operator or person inspecting or repairing an outboard motor.

OVERSEAS SERVICE OVERSEAS OPERATIONS YAMAHA MOTOR CO., LTD.

2N SERVICE MANUAL ©1986 by Yamaha Motor Corporation, USA 1st Edition - April 1983 2nd Printing- June 1986 ALL RIGHTS RESERVED BY YAMAHA MOTOR CORPORATION, U.S.A. CYPRESS, CALIFORNIA 90630

P/N LIT-18616-00-01

2N EXTERNAL VIEW

INDEX GENERAL INFORMATION PERIODIC INSPECTIONS AND ADJUSTMENTS

FUEL SYSTEM AND CARBURETION POWER HEAD OVERHAUL LOWER UNIT OVERHAUL RECOIL STARTER APPENDICES

CHAPTER 1. GENERAL INFORMATION OUTBOARD MOTOR IDENTIFICATION ................. 1-1 Outboard Motor Serial Number ................................. 1-1 Engine Serial Number .......................................... 1-1

SPECIAL TOOLS ............................................. 1-1 For For For For

Turn-Up ................................................... 1-1 Engine Service ............................................. 1-2 Lower Unit Service ......................................... 1-3 Electric Components ....................................... 1-3

SEALING AGENTS AND LUBRICANTS ................. 1-4 Sealing Agents ................................................ 1-4 Lubricants ...................................................... 1-4

NOTES ON SERVICE ....................................... 1-5 Fire Prevention ................................................ 1-5 Right Tools .................................................... 1-5 Oil and Grease ................................................. 1-5 Non-Reusable .................................................. 1-5 Tightening Torque ............................................. 1-5 Notes on Disassembly and Assembly ........................... 1-5

CHAPTER 1.

GENERAL INFORMATION OUTBOARD MOTOR IDENTIFICATION

SPECIAL TOOLS The proper special tools are necessary for complete and accurate tune-up and assembly. Using the correct special tool will help prevent damage caused by the use of improper tools or improvised techniques.

Outboard Motor Serial Number The outboard motor serial number is stamped on the plate attached to the upper part of the swivel bracket.

For Tune-Up 1. Compression gauge PIN. YU-33223

Engine Serial Number The engine serial number is stamped on the port side of the cylinder body.

This compression gauge is used to measure the engine compression pressure.

2.

Tachometer

PIN. YU-8036

This tachometer is used for checking the engine speed.

1-1

For Engine Service 1. Flywheel magneto holder PIN. YB-6139

3.

Bearing separator PIN. YB-6219

This tool is used for removing the bearing.

This tool is used for removing and tightening the flywheel securing nut.

2.

4.

Flywheel magneto puller PIN. YU-33270

Dial gauge set PIN. YU-3097 YU-1256 YU-1037 YU-1038

.I

I~

ÂŽ

!~I

~u 1/i

------~ This tool is used for removing the flywheel.

This dial gauge set is used for adjusting the ignition timing and the dial gauge is used for determing the gear shim.

1-2

For Lower Unit Service 1. Slide hammer P/N. YB-6096

3.

This handle is used to remove bushings from the lower casing.

This tool is used for removing the bearing and oil seal.

4.

2.

Handle P/N. YB-6229

Handle CD P/N. YB-06013 Attachment ÂŽ P/N. YB-06014 @ P/N. YB-06025

Bushing installer P/N. YB-06029, YB-6169

CD

ÂŽ This bushing installer is used when installing bushings in the lower casing.

For Electrical Components 1. Yamaha pocket tester P/N. YB-03112

These tools are used when installing bearings and oil seals.

This Yamaha pocket tester is used when measuring the resistance, voltage and amperage of electrical parts.

1-3

SEALING AGENTS AND LUBRICANTS

2.

Yamaha gear case lube.

P/N LUB-GEARL-11-00

Sealing Agents 1. Yamaha Bond No. 4 P/N. ACC-11001-30-00

J (350 cm.l /0.37 US qt/0.31 Imp qt)

(200 g)

Lubricants 1. Yamaha all-purpose grease (water-resistant grease) P/N LUB-GREAS-13-00

(250 g)

1-4

NOTES ON SERVICE Fire Prevention When servicing the fuel system, keep away from heat, sparks and open flames.

Right Tools Be sure to use the right special tool for the right part in order to protect the part from damage.

Always use the right tool and the right instrument. (Avoid using open-end wrenches as much as possible, and use box and socket wrenches.)

Oil and Grease Be sure to use genuine Yamaha oil and grease.

Never use any other brand.

Non-Reusable Always use new gaskets (packings), 0-rings, cotter pins and circlips for replacement.

Tightening Torque Be sure to keep to tightening torque specifications.

When tightening bolts, nuts and screws, start with a larger-diameter one and from an innerpositioned one to an outer-positioned one in a criss-cross pattern.

Notes on Disassembly and Assembly 1. Parts should be blown off with compressed air whenever they are disassembled.

2. Contact surfaces of moving parts should be oiled when they are assembled.

3. Make sure that parts move smoothly after each section of the machine is assembled.

1-5

CHAPTER 2.

PERIODIC INSPECTIONS AND ADJUSTMENTS INTRODUCTION ................................................ 2-1 PREDELIVERY SERVICE ....................................... 2-1 Handling Notes of Cardboard Crates ................................ 2-1 Notes on Transportation ........................................... 2-2 Predelivery Check .................................................. 2-2

PERIODIC INSPECTIONS AND ADJUSTMENTS ......... 2-5 Maintenance Interval Charts ....................................... 2-5 Spark Plug ........................................................ 2-6 Ignition Timing Adjustment ........................................ 2-6

CHAPTER 2.

PERIODIC INSPECTIONS AND ADJUSTMENTS < Handling

INTRODUCTION

instruction marks>

I his chapter includes all information necessary to perform recommended inspections and adjustments. These preventive maintenance procedures, if followed, will ensure more reliable outboards operation and a longer service life.

The need for costly overhaul work will be greatly reduced. This information applies to outboards already in service and to new outboards that are being prepared for sale. All service technicians should be familiar with this entire chapter.

This arrow mark indicates the top of the crate.

Be sure to load, unload, or store the crate with this mark pointing upward.

PREDELIVERV SERVICE Handling Notes of Cardboard Crates You will find the following marks on the crate sides. Read the explanation of these marks carefully when handling a crate.

This mark indicates .thaf the crate should be kept dry. Also avoid excessively humid places for storage.

This mark indicates that the crate content is fragile. Do not drop the crate or subject it to sharp bumps or shocks.

2-1

Notes on Transportation Observe the following in crate transportation. â&#x20AC;˘ Select a level, dry, and well-ventilated place for storage. â&#x20AC;˘ When moving or transporting a crate, take special care not to drop or bump it.

Predelivery Check 0

Contained in the packing

CD

Outboard motor

(2:) Owner's manual @ Service tools @ Emergency starter rope @ Spark plug @Tag

NOTE: ------------------------Each crate contains two 2N.

2-2

D Check engine exterior • Check for scratches or deformation.

• Patch up any scratched or peeled-off surface with a paint of identical color.

D Checking the gear oil level Remove both oil drain and oil level plugs, and add the gear oil through the oil drain plug hole. If the oil overflows the oil level plug hole, the oil level is correct. Otherwise, add the oil until it overflows the oil level plug hole.

D Steering Check to see if the engine can be turned 360° smoothly. If stiff, turn the wing bolt on the swivel bracket counterclockwise. If too light, turn the bolt clockwise.

GEAR OIL QUANTITY: 45 cm 3 (1.52 US oz, 1.58 Imp oz) GEAR OIL TYPE:

1. Oil level plug

D Throttle lever Check to see if the throttle lever can be moved smoothly. If stiff, turn the screw on the end of the throttle lever counterclockwise and if too light, turn the screw clockwise.

2. Oil drain plug

D Tilt-up Check to see if the engine is hard to tilt up or comes down of its own weight after tilt up. If hard, loosen the nut tightening the clamp brackets, and if too loose, retighten.

TIGHTENING TORQUE: 18 Nm (1.8 m·kg, 13 ft·lb)

2-3

0

Test-run (on the test tank)

• Never operate the engine even momentarily without running cooling water.

• When making a test in a test tank, be sure to mount the specified test propeller on the engine.

• Check the recoil starter for proper operation.

• Check to see wheather cooling water is spouting out of the pilot hole.

• Check to see that the engine speed is between 4,000 r/min and 5,000 r/min at fullthrottle.

• Check to see that the engine speed is between 1,150 r/min and 1,250 r/min at closed-throttle.

• Check the engine and gear case for abnormal noise.

• Check the operation of the engine stop button.

0

Clean up Clean the outboard thoroughly after the test. Wipe the outboard with a clean rag.

During the wipe down, check all compornents for nicks, scratches or other signs of damage.

0

Delivery When the outboard is delivered to the new owner, make sure he is familiar with all the operating controls. Advise him of break-in procedures. Let him know if there are any service or operationai problems peculiar to his locale that may require extra attention on his part.

2-4

PERIODIC INSPECTIONS AND ADJUSTMENTS Maintenance Interval Charts The following charts should be considered strictly as a guide to general maintenance and lubrication intervals.

Depending on operating conditions, the intervals of maintenance should be changed.

â&#x20AC;˘General maintenance intervals

((Unit: hours)) Initial Remarks

Item Fuel tank

Clean/ Flush Check for cracking and leakage/

Fuel line

Replace if necessary

Carburetor

Check operation/ Adjust if necessary Inspection/ Cleaning and adjust/

Spark plug

Replace if necessary Check head bolts for tightness/

Cylinder head

Torque bolts to specification if necessary

100

100

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Cooling system

0

Check/ Adjust if necessary Check pilot water/ Check water pump and water passage if necessary

0

0

â&#x20AC;˘ Lubrication intervals -Item

Off

50

Decarbonize Ignition timing

Thereafter every

10

season

((Unit: hours)) Remarks

Type (Recommended lubricants)

Initial 10

50

Thereafter every 100

100

Off season

Throttle control lever

Apply lightly

Check

0

0

0

Choke lever

Apply lightly

Check

0

0

0

Check

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Swivel bracket

Apply fully

Clamp bolt

Apply lightly

Propeller shaft

Applly lightly

Recoil starter

Apply lightly

Gear oil

Replace

(Yamaha all-purpose grease, P/N LUBGREAS-13-00)

0

0

0

Yamaha gear case lube, P/N LUB-GEARL-11-00)

2-5

0

Check

Spark Plug

. 1.

Check electrode condition and wear, insulator color and electrode gap.

2. Clean the spark plug with spark plug cleaner if necessary. Use a wire gauge to adjust the plug gap to specification.

3. If the electrode becomes too worn, replace the spark plug.

4. When installing the plug, always clean the gasket surface, wipe off any grime that might be present on the surface of the spark plug, and torque the spark plug properly.

STANDARD SPARK PLUG: B-5HS (NGK) SPARK PLUG GAP: 0.5-0.6 mm (0.020- 0.024 in) SPARK PLUG TIGHTENING TORQUE: 20 Nm (2.0 m ·kg, 14 ft ·lb) A: Decreasing gap

B-5HS

0.5-0.6 mm (0.020- 0.024 in)

Ignition Timing Adjustment 1. Adjust the breaker so that the maximum breaker point gap is 0.35 mm (0.014 in) when the magneto rotor is turned.

NOTE=------------------~--­ A part of the crankshaft is designed as a cam by which the breaker points are opened and closed.

To adjust the point gap, loosen the breaker plate set screw, and using a slotted-head screwdriver, change the breaker plate slightly.

2-6

B: Increasing gap

2.

Remove the spark plug and install the dial gauge in the spark plug hole in the cylinder head using the dial stand.

3.

Rotate the magneto rotor until the piston reaches top dead center (TDC). When this happens, the needle on the dial gauge will stop and reverse directions even though the rotor is being turned in the same direction. Zero the dial gauge at TDC.

4.

Connect the primary lead (white) of the magneto to the positive lead (red) of the point checker, and ground the other lead (black) of the point checker to the engine.

If the ignition timing adjustment is impossible by changing the point gap, replace the contact breaker and readjust the timing.

PO•~f CtlfCICER' 1 ~~-----

1. Black

5.

2. Red

-~----t_·

3. White

Slowly rotate the magneto rotor counterclockwise. The timing is correct if the pointer of the point checker moves from "OPEN" to "CLOSE" at 1.11 ±0.12 mm (0.044±0.0047 in) B.T.D.C.

"OPEN" ___,.. "CLOSE"

IGNITION TIMING: B.T.D.C. 1.11 ±0.12 mm (0.044±0.0047 in)

* If the point checker pointer swings from "OPEN" to "CLOSE" before passing 0.99 mm (0.039 in) B.T.D.C., adjust the point gap to 0.35-0.4 mm (0.014-0.016 in).

* If the point checker pointer swings from "OPEN" to "CLOSE" after passing 1.23 mm (0.048 in) B.T.D.C. adjust the point gap to 0.35-0.30 mm (0.014-0.012 in).

2-7

CHAPTER 3.

FUEL SYSTEM AND CARBURETION DESCRIPTION .................................................. 3-1 FUEL TANK .................................................... 3-2 Description ...................................................... 3-2 Removal ......................................................... 3-3 Cleaning, Inspection and Repair .................................. 3-3 Installation ...................................................... 3-3

CARBURETION ................................................ 3-4 Description ...................................................... 3-4 Fuel flow ........................................................ 3-5 Removal ......................................................... 3-6 Disassembly ..................................................... 3-6 Cleaning, Inspection and Repair .................................. 3-7 Assembly ........................................................ 3-8 Installation ...................................................... 3-9

CHAPTER 3.

FUEL SYSTEM AND CARBURETION DESCRIPTION

e,

The model 2N has a plastic fuel tank (capacity: 1.2 0.32 US gal, 0.26 Imp gal) on the cylinder block, and fuel flows down to the carburetor of its own weight .

. . Fuel

<::=J Air ¢J

3-1

Mixture

FUEL TANK

b. Fuel cock The fuel cock has a filter in it to keep impurities from entering the carburetor.:!

Description The fuel tank is fitted with a filler cap and a fuel cock. a. Fuel tank filler cap The fuel tank filler cap has an air vent whichcan be opened and closed by turning the air screw. The air vent prevents the pressure ¡in the fuel tank from becoming negative during operation.

1. Fuel filter â&#x20AC;˘

1.

2, 3.

4.

Air

Air screw Packing Packing Spring

3-2

Removal

3.

Loosen the screw, loosen the band, and remove the fuel cock.

WARNING: Gasoline is highly flammable and explosive. Avoid smoking while servicing the fuel system. Also, keep away open flames and sparks.

1.

Set the fuel cock to "OFF", and remove the clips from the hose between the fuel cock and carburetor, then remove the hose.

Cleaning, Inspection and Repair Fuel system trouble often stems from fuel leakage caused by a worn gasket or packing, or a fuel flow hindered by a clogged fuel filter or air vent. When checking the fuel system, proceed as follows:

WARNING: When fuel remains in the fuel tank, set the fuel cock to "ON" after removing the fuel hose, and drain the tank.

a. Fuel tank Add a small quantity of suitable cleaning solvent to the fuel tank interior by shaking the tank. After cleaning, drain off the cleaning solvent completely.

2.

b. Fuel tank filler cap Replace a worn packing, or clean a clogged air hole in the gasket plate or air vent. c. Fuel cock Thoroughly wash the fuel filter fitted to the inlet in a suitable cleaning solvent.

Remove the two nuts and one bolt, and remove the fuel tank.

NOTE: ----------------------If the fuel cock is leaky, replace it as a fuel cock assembly. It cannot be disassembled.

Installation 1. Install the fuel cock on the fuel tank, and secure it with the screw.

2. Secure the fuel tank to the cylinder block with the two nuts and one bolt.

3. Connect the fuel hose to the carburetor and fuel cock, and hold it with the clips.

3-3

CARBURETION Description The carburetor is of a singlebarrel, float-feed type and provided with a manual choke:.- The front panel plays a role of the intake silencer. Fuel is metered by the jet needle, and air by the throttle valve so tbat the optimum air-fuel ratio can be obtained.

1.

2.

3.

4, 5.

6.

7.

8.

Valve seat Main nozzle Main jet Float Choke valve Idle adjust screw Throttle valve Jet needle

3-4

Fuel flow

ÂŽ 1. Throttle valve Main jet Main nozzle Jet needle Throttle bar Choke valve

2.

3.

4.

5.

6.

.Fuel

<::JAir

When the choke valve (6) is operated, the air flow through the venturi decreases and thus, a rich mixture required for starting the engine can be obtained.

When a partial vacuum is produced in the crankcase, fuel flows from the main jet (2) through the mC!in nozzle (3) to the jet needle (4) by which the fuel is metered. The metered fuel is mixed with the air supplied through the air passage, and the resultant mixture is atomized in venturi before streaming into the crankcase. When the throttle opening is increased by operating the throttle control lever, the jet needle (4) is pulled upward and thus, the fuel flow increases. Also, the throttle valve (1) is pulled upward at the same time and therefore, mixtures of the optimum air-fuel ratio are supplied to the crankcase.

NOTE: _______________________ Turning in the idle adjust screw opens the throttle valve. This adjusts the idle speed. Turning the screw in increases the engine speed, and turning it out decreases the speed.

3-5

Removal 1. Disconnect the engine stop button lead (white) and ground lead (black).

Disassembly 1. Remove the circlip and screw, and remove the throttle control lever from the carburetor body.

2.

Loosen the carburetor mounting screw, and pull out the carburetor.

3.

Pull out the choke knob, remove the screw securing the knob to the throttle control lever, and remove the knob. Next, remove the screws on the intake silencer, and remove it.

3-6

2.

Loosen the bolt, loosen the top mixing chamber, and remove the throttle valve and jet needle.

Cleaning, Inspection and Repair

1. Checking fuel and air passages Check the carburetor body, its parts and the fuel and air passages for fouling or clogging. Clean fouled parts with suitable cleaning solvent and blow out clogged passages with compressed air.

WARNING: Be sure to direct compressed air downward as the cleaning solvent may get in your eyes or those of other persons, or small carburetor parts may be blown off.

1. Top mixing chamber 2. Throttle valve

3.

3. Jet needle

2.

Remove the screws, and remove the float chamber and float. Next, pull out the float pin, and remove the float arm and needle valve.

Remove the idle adjust screw from the carburetor body.

Checking the needle valve and valve seat Check the needle valve and valve seat for wear and, if both or either is worn, replace them.

GOOD CONDITION

l. Float chamber 2. Float 3. Float arm

4.

4. Needle valve 5. Float pin 6. Idle adjust screw

UNSUITABLE

Remove the nut, and remove the valve seat. Next, remove the main jet, main nozzle, and float chamber gasket.

4~ 1. Valve seat 2. Main jet

3. Main nozzle 4. Float chamber gasket

3.

CD 3-7

Checking the throttle valve and jet needle Check the throttle valve and jet needle for wear, and replace them as required.

NOTE=----------~----~~--­

Assembly

Before placing the float on the float arm, adjust the height of the float arm so that the float arm is 4 ± 0.5 mm (0.157 ± 0.020 in) above the float chamber gasket surface.

Always use new gaskets as a preventive measure against fuel leakage.

1. Install the valve seat in the carburetor body, and tighten the nut. Nex.t, hook the end of the needle valve onto the slit in the ·float arm, Insert it into the valve seat, and hold the float arm with the float pin.

4. Fit the circlip iri the· second notch from the top of the jet needle, install the spring seat, and insert the throttle valve into it.

5. Install the throttle bar, spacer; cap, bolt, stay, top mixing chamber, and spring, in that order. The bolt should be temporarily screwed into the top mixing chamber.

6. Hook the end of the throttle bar onto the slit in the throttle valve.

7. Install the top mixing chamber on the carburetor body, and bolt the stay.

NOTE: _______________________ 2.

Install the main nozzle in the carburetor body, and install the main jet.

3. Place the float on the float a~m, install the float chamber gasket on the float chamber, and secure the float chamber to the carburetor with the two screws and two washers.

•

•

TIGHTENING TORQUE: 1.5 Nm (0.15 m ·kg, 1.1 ft ·lb)

3-8

The throttle valve should be inserted with the slitted side facing toward the valve seat. Th_e carburetor body has a projection (serving as a stopper) and therefore, it is impossible to insert the throttle valve from the other side.

When bolting the stay, itsl)ould be positioned so that its end contacts the projection on the carburetor body.

8.

Installation 1. Secure the carburetor to the intake silencer with the two screws. Next, install the choke knob and throttle control knob.

2. Install the carburetor on the engine, and secure it with the screw.

Apply Yamaha all-purpose grease, P/N LUB-GREAS-13-00, to the idle adjust screw, and screw it into the carburetor body through the spring.

NOTE: ----------------------After completing engine assembly, the idle adjust screw must be adjusted so the engine idles at 1,150 to 1,250 r/min.

9.

, WARNING:

Make sure the 0-ring is installed between the carburetor and engine. Lack of the 0ring will result in fuel leakage.

Secure the throttle control lever to the carburetor body with the circlip, screw, and spring.

3.

3-9

Connect the engine stop button lead (white), and connect the ground lead (black).

CHAPTER 4. POWER HEAD OVERHAUL DESCRIPTION ................................................... ·4-1 PREPARATION FOR REMOVAL ............................ ·4-1 REMOVAL ....................................................... ·4-1 DISASSEMBLY ................................................. ·4-3 CLEANING, INSPECTION AND REPAIR .................. ·4-5 Cylinder Head .................................................... ·4-5 Block ...................................................... ·.·.· .... ·4-6 Piston ............................................................ ·4-6 Piston Rings ...................................................... ·4-7 Piston Pin and Bearing ................................ ·............ ·4-7 Crankshaft ....................................................... ·4-8 Reed Valve Assembly .............................................. 4-8 Crankshaft Main Bearings ......................................... ·4-9 Electrical Parts ................................................· .... ·4-9

ASSEMBLY AND ADJUSTMENT ......................... ··4-11 Important Information ........................................... ·4-11 Piston and Crankshaft ........................................... ·4-11 Block ..................................................· ......... ·4-12

INSTALLATION ................................................ ·4-14

CHAPTER 4.

POWER HEAD OVERHAUL DESCRIPTION The model 2N is a 2-stroke, water-cooled, 43 cm 3 (2.62 cu.in), single cylinder engine. The Schnurle scavenging system is used, and the ignition system is the flywheel magneto system with a fixed magneto base.

PREPARATION FOR REMOVAL 1.

All dirt, mud, dust and foreign material must be cleaned from the engine before the engine is removed and disassembled.

This will help keep foreign material out of the engine.

2. Before engine removal and disassembly, be sure that you have the proper tools and cleaning equipment. With them, you can perform your work cleanly and efficiently.

3. During engine disassembly, clean all parts and place them in trays in their order of disassembly. This will speed up assembly and help assure that all parts are correctly reinstalled in the engine.

REMOVAL 1.

Remove the 10 screws and remove the apron.

4-1

2.

Remove the three bolts and remove the recoil starter.

The major load must be carried in the direction of the arrow. If not, the holder can easily slip off.

3.

Remove the three screws and remove the starter pulley and cover.

DIRECTION OF MOVEMENT

r::fJ

5. Using the flywheel magneto puller (YB-32270), remove the flywheel magneto.

The flywheel magneto puller set bolts must be tightened evenly so that the flywheel magneto puller plate is held parallel to the flywheel top.

4. Loosen the flywheel nut using the flywheel magneto holder (YB-6139) and 17 mm socket wrench. Do not remove the nut but screw it out up to the end of the crankshaft.

4-2

9.

6.

Remove the 6 bolts securing the power head, and remove the power head.

Remove the woodruff key from the crankshaft keyway.

DISASSEMBLY 1.

7.

8.

Remove the fuel system parts. (Refer to Chapter 3. FUEL AND CARBURETION -Removal.)

Remove the two bolts, and pull out the magneto base.

4-3

Remove the four bolts and remove the cylinder head.

2.

Remove the four bolts and remove the stay and reed valve.

5.

3.

Remove the clips and pull out the hose.

By tapping the crankshaft with a plastic hammer, slightly move it off its position.

Hold the crankshaft, and pull the piston out of the cylinder. Next, remove the oil seals and washer.

0 4.

Remove the two bolts and divide the crankcase.

6.

4-4

0

Remove the piston pin clips from the piston, and push the piston pin out, then remove the connecting rod small-end bearing from the connecting rod.

7.

Remove the piston rings from the piston.

CLEANING, INSPECTION AND REPAIR Cylinder Head 1. Using a rounded scraper, remove any car- ¡ bon deposits from combustion chamber.

Take care to avoid damaging the spark plug threads. Do not use a sharp instrument. Avoid scratching the aluminum.

2. Remove the salt or fur from the cylinder head water jacket using a scraper.

3. Measure the warpage of the cylinder head using a straight edge. The warpage should not exceed the specified limit; if necessary, resurface the cylinder head.

8. Using the bearing separator (YB-06219) and a press, remove the bearings from the crankshaft.

CYLINDER HEAD WARPAGE: less than 0.1 mm (0.004 in) When removing the bearings from the crankshaft, be sure to hold the crankshaft with your hands, or it will fall off and you may get injured.

Correct by resurfacing as follows: Place 400 rv 600 grit wet sandpaper on the surface plate and resurface the head using a figure-eight sanding pattern. Rotate the head several times to avoid removing too much material from one side.

4-5

Block 1. Visually check the cylinder walls for scratches. If vertical scratches are evident, the cylinder wall should be rebored or the cylinder should be replaced.

2. Remove any deposits from the cylinder exhaust port.

3. Check the block water jacket and cooling water passages for dirt, salt, sand, or other deposits and clean as required. Also patch up any part from which anticorrosion paint has come off.

4. Hone the cylinder bore using a hone with fine stones. Hone no more than required to remove all wear marks.

c

1. Cylinder gauge

Piston 1. Remove any carbon deposits from the piston crown.

2. Carefully remove any carbon deposits from the ring grooves with the filed end of a ring.

3. Remove all score marks and la.cquer deposits from the sides of the piston using 600- 800 grit wet sandpaper. Sand in a crisscross pattern. Do not sand excessively.

4. Measure the outside diameter of the piston at the piston skirt.

Measurement should be made at a point 10 mm (0.4 in) above the bottom edge of the piston. Place the micrometer at right angles to the piston pin.

CYLINDER BORE Standard

Wear limit

39+g.02 mm (1.54+g.OOOB in)

39.5 mm (1.56 in)

5. Using a cylinder gauge set to standard bore size, measure the cylinder. Measure front-to-rear and side-to-side at top, center and bottom just above the exhaust port. Take minimum and maximum measurements. If over tolerance and not correctable by honing, rebore to next oversize.

MAXIMUM ALLOWABLE TAPER: 0.08 mm (0.003 in) MAXIMUM ALLOWABLE OUT-OF-ROUND: 0.05 mm (0.002 in)

5. Determine piston clearance as follows: Minimum bore measurement - Maximum piston measurement = Piston clearance PISTON CLEARANCE: 0.03-0.04 mm (0.0012-0.0016 in)

4-6

Piston Rings 1. Measure the end gap of each piston ring.

Insert a ring into the cylinder and push it approximately 20 mm (0;8 in) into the cylinder. Push with the piston crown so the ring will be at a right angle to the cylinder bore.

2. Measure the ring end gap with a feeler gauge. If the end gap exceeds tolerance, replace the whole set of rings.

RING END GAP INSTALLED: Top/Second Minimum: 0.1 mm (0.004 in) Maximum: 0.3 mm (0.012 in)

Piston Pin and Bearing 1. Apply a light film of oil to the pin and the bearing surfaces. Install in the connecting rod small end to inspect for wear. Check for play. There should be no noticeable vertical play. If play exists, check the connecting rod small end for wear. Replace the pin, connecting rod and/or bearing as required.

2. The piston pin should have no noticeable free play in the piston. If the piston pin is loose, replace the pin and/or piston.

3. Check the pin and bearing for signs of heat discoloration. If excessive (indentation on pin, etc.), replace the pin and bearing.

3. Piston ring/ring groove fit must have correct clearance. If the piston and ring have already been used in the engine, the ring must be removed, the ring groove cleaned of carbon, then the ring should be reinstalled. Use a feeler gauge to measure the gap between the ring and the land.

SIDE CLEARANCE: Top/Second 0.03-0.07 mm (0.001-0.003 in)

4-7

Crankshaft 1. Check the connecting rod axial play at the small end to determine the amount of wear of the crank pin and of the big-end ¡ bearing.

If small end play exceeds tolerance, disassemble the crankshaft and check the connecting rod, crank pii1 and big end bearing ..

Replace defective parts. Play after reassembly should be within specification.

ROD AXIAL PLAY: 2 mm (0.08 in)

Reed Valve Assembly 1. Check the reed valve. If it is cracked or warped, it will not seal with the seat.

2. Check valve stopper clearance. If beyond tolerance, adjust the stopp,er or replace as required.

2. Check the connecting rod side clearance at the big end.

If axial play exceeds tolerance,. disassemble the crankshaft and replace any worn parts. Big end axial play should be within specification.

VALVE STOPPE.R CLEARANCE: 6 mm (0.24 in)

ROD SIDE CLEARANCE Minimum 0.30 mm (0.012 in)

Maximum

-

If clearance is 0.2 mm (0.008 in) more or less . than specified, replace the valve stopper.

0.60 mm (0.024 in)

3. Support the cra,nkshaft at both ends on V-blocks. Rotate the crankshaft in the Vblocks and measure the runout at the main bearing journals. Use a dial gauge.

Check crankshaft assembly runout (misalignment of crankshaft parts).

Dial gauge readings should be within specification.

Correct any misalignment by tapping the flywheel with a brass hammer and/or by using a wedge.

3. Check the reed valve for bending and, if beyond tolerance, replace.

DEFLECTION TOLERANCE Left side

Right. side

0.02 mm (0.0008 in)

0.02 mm (0.0008 in)

REED VALVE BENDING LIMIT: 0.3 mm (0.012 in)

4-8

4.

During reassembly, clean the block, reed and stopper plate thoroughly. Tighten each screw gradually to avoid warping.

<Measuring the resistance of the primary winding> Set the tester to the R x 1 scale, and zero the meter by turning the "00 ADJ" knob. When zeroing the meter touch the positive and negative leads of the tester to each other.

TIGHTENING TORQUE: 0.7-0.9 Nm (0.07 -0.09 m ·kg, 0.51-0.65 ft ·lb)

Connect the positive lead of the tester to the primary side terminal, and ground the negative lead to the ignition coil body.

NOTE: ----------------------During reassembly, note the cut in the lower corner of the reed and stopper plate. Use as an aid for direction of reed installation.

Crankshaft Main Bearings Thoroughly clean the crankshaft, sparingly oil both the upper and lower ball bearings and slowly turn the outer races with your hand.

If rough spots are noticed, replace the ball bearings.

1. Red

2. White

3. Black

STANDARD RESISTANCE: 1.060 ± 10% at 20°C (68°F)

Electrical Parts a. Ignition coil 1. Check the high-tension wire and spark plug cap for electrical leakage resulting from cracks or breaks.

2. Measure the resistance of the primary and secondary windings of the ignition coil.

If the tester readings are out of specification, replace the ignition coil.

<Measuring the resistance of the secondary winding> Set the tester to the R x 1K scale, and zero the meter by turning the "00 ADJ" knob. When zeroing the meter, touch the positive and negative leads of the tester to each other.

4-9

. STANDARD CAPACITY: 0.25/LF :±: 10% at 20°.C (68°F)

!i 0 ~- ' ·:g .B~.111. ~«!9....(]~ '9t,~~ 2

1

II

Connect the posi~ivp lead of the tester to the secondary side >terminal, and ground the negative lead to the ignition coil body.

1. Black

·-""""'

i ;._.,.__

f1

~~

2. R~d

2.

STANDARD RESISTANCE: 6.05k0 ± 10% at 20°C (68°Fl. b. Condenser 1. Capacity test For capacity test, use the Electro Tester.

Set the selector switch to "C. CAPACITY".

Connect a 12-V battery to the tester, and turn the "POWER SOURCE" switch to "12V".

Set the calibration switch to "CAL", and set the tester needle to 0.2/LF in the green zone.

Set the calibration switch to "TEST", and connect the condenser. If the tester readings are within the range of specified values, the condenser capacity is correct.

4-10

Insulation test For insulation test, use the Electro. Tester.

Set the selector switch to "INSULATION".

Use a 12V battery as the power source, and turn the "POWER SOURCE" switch to "12V".

Set the calibration switch to "CAL", and set the tester needle to zero by turning the. zero adjuster.

Turn the calibration switch to "TEST", and connect the condenser. If the tester needle swings once and stays pointing to 5 MO or more the condenser insulation resistance is correct.

•

ASSEMBLY AND ADJUSTMENT

•

Important Information 1. Gasket and seal All gaskets and seals should be replaced when the engine is overhauled. All gasket surfaces and oil seal lips must be cleaned.

2. During reassembly, apply the proper type of oil to all engine moving parts and all bearings.

3. Circlip All circlips should be inspected carefully before reassembly. Always replace piston pin clips after one use. Replace distorted circlips.

'·0 • · ·- .... ao nK111DTDTIII

•

•

...

~~~·

.. ·· .

Q9.9.

0

o: ~ -~~-.

Piston and Crankshaft 1. Fit the piston rings into the grooves.

2. Align each ring end gap with the locating pin.

NOTE: _______________________ The condenser should be discharged by contacting the lead wire to the condenser body after the insulation resistance test, because a electrical charge is stored during the test.

NOTE=------~--------------• Take care not to scratch the piston or brake piston rings.

• Piston rings should be replaced as a set.

• After fitting. the rings, check that they move smoothly.

c. Contact breaker Check the contact breaker points for burned or dirty surfaces. Check for misalignment of contacts. Repair or replace as required. The fixed contact point surface is curved like a hemisphere so that the point gap can easily be adjusted, but it is difficult to smooth out the surface into the original shape using a point file, sandpaper ( # 400- # 600), or oil stone, so it may be shaped into a flat surface. The points should be smoothed one by one.

4-11

3.

Properly support the crankshaft half to keep from altering the alignment, and press the main bearings on the crankshaft. Make sure the piece used to press the bearing on contacts the inner bearing race only.

NOTE: ---------------------The bearing should be installed so that the stamp mark indicating the size faces outward.

Block 1. Thoroughly clean the bench, and place the block on the bench with the head side down.

1. Press piece 2. Support plate

4.

Fit the small end bearing in the connecting rod small-end, and insert the piston pin into the piston pin hole in the piston and small-end. Fit the piston pin clips to the piston pin holes on both sides of the piston.

Apply 2 stroke engine oil to the cylinder.

2. Apply the 2 stroke engine oil to the piston and its ring grooves.

3. Align the piston ring end gaps with the respective locating pins.

4. Insert the piston into the cylinder and push down the crankshaft so it fits in the block. Ro'tate the upper and lower bearings so the locating pins fit in the slots in the block.

NOTE: -----------------------

• • 5.

The piston should be installed with the "UP" mark on the piston crown facing upward (toward the flywheel magneto).

Make sure the piston pin clip is securely fitted in the piston pin hole.

Install the oil seal on the upper crank, and install the washer and oil seal on the lower crank.

NOTE: ----------------------• •

Before installing the oil seal, grease the lip.

Make sure the oil seal faces in the correct direction.

4-12

5.

Drive two dowel pins into the mating surface of the block with the crankcase.

6. Apply Yamaha Bond No.4 to the mating surface of the crankcase, and secure the case to the block with the. two bolts.

TIGHTENING TORQUE: · 1st step 5 Nm (0.5 m ·kg, 3.6 ft ·lb) 2nd step 10 Nm (1.0 m·kg, 7.2ft·lb)

NOTE: _______________________ 9.

The left-side bolt should also be used to secure the clamp to the block.

Make sure the mating surface of the cylinder body with the cylinder head is free of dust, then install the cylinder head gasket and cylinder head on the cylinder body and tighten the bolts.

NOTE: _______________________ • •

TIGHTENING TORQUE: 1st step 5 Nm (0.5 m ·kg, 3.6 ft ·lb) 2nd step 10 Nm (1.0 m ·kg, 7.2 ft ·lb)

1. Clamp

7.

Fit the hose over the joint pipes and hold it with the clips.

8.

Secure the valve seat packing and reed valve stay to the crankcase with the four bolts. These bolts also serve to hold the crankcase to the cylinder body.

Do not apply any sealing compound to the cylinder head gasket.

Coat the bolt threads with LOCTITE® and tighten the bolt.

TIGHTENING TORQUE: 1st step 5 Nm (0.5 m ·kg, 3.6 ft ·lb) 2nd step 10 Nm (1.0 m ·kg, 7.2 ft ·lb)

4-13

3.

INSTALLATION 1. Thoroughly remove the gaskets from the mating surfaces of the upper casing and engine unit and from the exhaust guide.

Place the lower exhaust; exhaust guide, and upper exh .... ustguide between the upper casing and engine unit, then secure them to each other with the six bolts.

Fit the woodruff key to the crankshaft, and install the flywheel magneto. Using a 17 mm socket head wrench and the flywheel magneto holder (YB-6139), tighten the nut.

TIGHTENING TOROU!:: 40-50 Nm (4-5 m·kg, 29-36 ft·lb)

NOTE: _______________________

• • • •

Make sure the dowel pin is fitted to the upper casing.

Apply Yamaha Bond No. 4 to the upper exhaust gasket and lower exhaust gasket.

Apply LOCTITE® to the bolt threads, and tighten the bolts in two steps.

Apply Yamaha. all-purpose grease, P/N LUB-GREAS-13-:-00·, to the lower part of the crankshaft.

4. · Secure the cover and starter pulley with the three screws.

5. Install the fuel system parts; (Refer to Chapter 3. FUEb. SYSTEM AND CARBURETION - Installation.)

6. Secure the recoil starter with the three bolts.

7. Secure the apron with the 10 'screws.

2.

Secure the magneto base to the engine with the two bolts.

4-14

CHAPTER 5. LOWER UNIT OVERHAUL DESCRIPTION .................................................... 5-1 Preparation for Removal ........................................... 5-1

LOWER CASING REMOVAL ................................. 5-1 UPPER CASING DISASSEMBLY ............................ 5-2 Bracket ........................................................... 5-2

INSPECTION, CLEANING AND REPAIR .................. 5-3 Upper Casing ..................................................... 5-3 Bushings, Friction Piece and Wing Bolt ............................ 5-3 Transom Clamp Screws ........................................... 5-3 Receiver Bolt ..................................................... 5-4 Water Tube ....................................................... 5-4

UPPER CASING

ASSEMBL~/

................................ 5-4

LOWER CASING DISASSEMBLY .......................... ·5-5 Preparation for Disassembly ...................................... 5-5 Disassembly ..................................................... _. 5-5

INSPECTION, CLEANING AND REPAIR ..................

5-8

Water Pump ...................................................... 5-8 Gears and Propeller Shaft ......................................... 5-8 Bearing and Bushing .............................................. 5-9 Shear Pin, Cotter Pin and Propeller ................................ 5-9 Drive Shaft ....................................................... 5-9

ASSEMBLY ..................................................... 5-10 INSTALLATION ................................................ 5-14

4.

Before disassembling the gear case, drain the gear oil into a tray. Use care not to spill the oil on the floor.

5. When disassembling the lower unit, use a repair stand.

DESCRIPTION In this 2N, the drive shaft is in constant mesh with the propeller shaft so that the propeller is always turning clockwise.

To back the boat, the motor has to be turned 180°; that is, a full-pivot steering system is employed. When the motor is in the reverse position, the swivel bracket engages with the clamp brackets to stop the motor from turning up due to the reverse thrust.

When the exhaust gases forced out of the engine enter the upper casing, they expand and as a result, the pressure decreases. The exhaust gases are mixed with the cooling water coming from the engine block and flow through the lower casing into water.

At low speeds, both of the exhaust gas pressure and the.,. boat speed are low. Thus, the water pressure around the exhaust outlet is higher than the exhaust gas pressure so that the exhaust gases flow out of the idle holes in the upper casings. The idle holes are provided with a cover to reduce the exhaust noise.

Cooling water is drawn through the holes in the lower part of the lower casing and supplied to the engine by the impeller keyed to the drive shaft. After cooling the engine, the water is mixed with the exhaust gases, and while cooling the upper casing, it flows out into water, together with the exhaust gases.

LOWER CASING REMOVAL 1.

2.

3.

4.

Preparation for Removal 1. All dirt, salt, dust, and foreign material must be cleaned from the engine before the lower unit is removed and disassembled. This will help keep foreign material out of the lower unit.

2. Before lower unit removal and disassembly, be sure that you have the proper tools and cleaning equipment. With them you can perform a clean and efficient job.

3. During lower unit disassembly, clean all parts and place them in trays in their order of disassembly. This will speed up assembly and help assure that all parts are correctly reinstalled in the lower unit.

Using the pliers provided, straighten the cotter pin and pull it out.

Remove the propeller.

Remove the shear pin.

Remove the two bolts securing the upper casing and lower casing.

1. Cotter pin

5.

5-1

2. Shear pin

Remove the lower casing pulling downward.

UPPER CASING DISASSEMBLY Before disassembling the upper casing, it is necessary to remove the power head (refer to "Power Head Removal" on page 4-1).

1.

Remove the securing bolt, and remove the steering handle.

4.

2.

Remove the water tube from upper casing.

Remove the four bolts securing swivel brackets 1 (front) and 2 (rear).

Bracket Remove the wing bolt and remove the friction piece.

Remove the clamp bolt and receiver bolt, and remove swivel bracket 1 (front) and thrust receiver.

NOTE: _______________________ A spring pin is fitted to the threaded end of the receiver bolt to prevent the wing nut from coming off. Be sure to remove the pin when removing the wing nut, and use care so that it is not lost.

1. Swivel bracket 1 (front) 2. Swivel bracket 2 (rear)

3.

Remove the 0-ring, pivot shaft bushings and exhaust cover from upper casing.

5-2

ÂŽ LEAKAGE

Bushings, Friction Piece and Wing Bolt Check bushings, friction piece and wing bolt for wear and salt deposit. Apply Yamaha grease A or replace part(s) as required.

WEAR 1.

2.

3.

4.

Wing bolt Friction piece Clamp bracket Thrust receiver

5. Cli:lnlp bolt 6. Receiver bolt 7. Spring pin

&

~ SALT DEPOSIT .

~(ft?@

\:::

INSPECTION, CLEANING AND REPAIR Wash all parts with suitable cleaning solvent in detergent and blow them dry with compressed air.

Transom Clamp Screws Check the transom clamp screws for salt deposits. Apply Yamaha grease A as required.

Upper Casing 1. Check the contact surface of the upper casing with the engine for scratches or water leakage. Replace if damaged.

2. Check the contact surface of the upper casing with the friction piece and bushings for wear.

5-3

Receiver Bolt Check the receiver bolt for bends or cracks, and replace it, as required.

BEND

Water Tube Check the water tube for clogging with dust or dirt, and clean it, if necessary.

2.

UPPER CASING ASSEMBLY

Install the 0-ring, pivot shaft bushings, and exhaust cover in the upper casing.

When installing the 0-ring and pivot shaft bushings, apply Yamaha all-purpose grease, P/N LUB-GREAS-13-00, to them.

NOTE: --------------------~ Always use new gaskets and 0-rings. Old ones may leak due to invisible scratches or stretching.

Apply grease to parts where specified.

1.

Install swivel bracket 1 (front) and thrust receiver between the right and left clamp brackets, and insert the clamp bolt and receiver bolt, then tighten.

When inserting the receiver bolt, grease (Yamaha all-purpose grease, P/N LUBGREAS-13-00) its threaded portion.

3.

Install the wing bolt, spring, and friction piece on swivel bracket 1 (front). When installing these parts, apply Yamaha allpurpose grease, P/N LUB-GREAS-13-00, to them.

4. Install swivel bracket 1 (front) and swivel bracket 2 (rear) on the upper casing.

CLAMP BOLT TIGHTENING TORQUE: M8 18.0 Nm (1.8 m ¡kg, 13.0 ft ¡lb)

5-4

LOWER CASING DISASSEMBLY

TIGHTENING TORQUE: M6 8.0 Nm (0.8 m 路kg, 5.8 ft 路 lb)

Preparation for Disassembly Remove the lower casing from the upper casing. See page 5-1 for removal.

To disassembly the lower casing, hold it with a repair stand. If no repair stand is available, grip the skeg in a vise. To protect the skeg against damage, wrap it with a rag.

Remove the upper casing gasket and anticavitation plate.

1. Upper casing gasket

5.

Install the steering handle and water tube. Apply Yamaha all-purpose grease, P/N LUB-GREAS-13-00, to the washer.

2. Anti-cavitation plate

Disassembly 1. Remove the oil level plug and oil drain plug, then drain the oil out of the gear case.

TIGHTENING TORQUE: M8 18.0 Nm (1.8 m 路kg, 13.0 ft 路lb)

NOTE: ----------------------1. Be sure to remove the drain plug first.

2. Let the gear oil drain into a tray so that it will not spill on the floor.

Should any gear oil spill on the floor, wipe it off immediately with rags.

5-5

1. Oil level plug

2.

2. Oil drain plug

Remove the two bolts securing the lower casing cap. Turn the cap to the right or to the left, and by tapping it with a softfaced hammer, remove the cap.

4.

Remove the drive shaft from the lower casing by pulling it upward, and remove the pinion gear, washer and gear adjust shim (if so equipped) from the gear case.

5. Remove the propeller shaft and forward gear (as an assembly) and gear adjust shim (if so equipped).

1. Lower casing cap

3.

Remove the circlip on the drive shaft end, and remove the two bolts securing the water pump housing cover.

1. Pinion gear 2. Washer 3. Gear adjust shim

5-6

4. Propeller shaft 5. Foward gear

6.

Remove the water pump housing cover, cartridge outer plate, impeller and dowel pin from the drive shaft, and remove the insert cartridge and oil seal protector from the lower casing.

b. Drive shaft oil seals.

Install the puller attachment and slide hammer in the drive shaft oil seals, tighten the puller, and remove the seals with the slide hammer. c. Propeller shaft oil seal.

Install the puller attachment and slide hammer in the propeller shaft oil seal, tighten the puller, and remove the seal with the slide hammer.

\

ÂŽ 1. Water pump housing cover 2. Cartridge outer plate 3. Impeller

4. Dowel pin 5. Insert cartridge 6. Oil seal protector

1. Bearing and oil seals a. Propeller shaft bearing Install the bearing puller attachment on the slide hammer (YB-6169), install the puller in the bearing, and tighten the puller so the claws hold the inner race of the bearing; see the illustration. Remove the bearing with the slide hammer.

5-7

2.

Drive shaft bushings Drive out the bushing downward at the lower end of the drive sh~ft. To remove, use the handle (YB-6027) ..¡

WEAR

Gears and Propeller Shaft 1. Check the tooth faces of the forward gear and pinion for pitting, wear, cracks, or chips, and replace, as required.

2. Check the propeller shaft for breaks or cracks, and replace, as required.

INSPECTION, CLEANING AND REPAIR

NOTE=----------~----------------------------------------­ The forward gear is press-fitted to the propeller shaft and therefore, it must be replaced as an assembly with the propeller shaft, if it has to be replaced.

Wash all parts with suitable cleaning solvent in detergent and blow them dry with compressed air.

Water Pump 1. Check the water passage for clogging, and clean, if necessary.

2. Check the impeller for broken or cracked blades or worn keyway, and replace the impeller, as required.

3.

DAMAGE

Check the contact surface of the insert cartridge with the impeller for wear or cracks, and replace it, as required.

5-8

Bearing and Bushing 1. Check the bearing for burning or pitting, and replace it, as required.

2. Check the bushing for wear, cracks, or breaks, and replace it, as required.

PITTING

(860001

WEAR

Drive Shaft 1. Check the drive shaft for runout. Place the drive shaft on V-blocks, and measure the drive shaft runout with a dial gauge.

Shear Pin, Cotter Pin and Propeller 1. Check the shear pin and cotter pin for breaks or cracks, and replace them, as required.

2. If the propeller is worn excessively, the engine speed will exceed 5,000 r I min at full-throttle. In this case, the propeller has to be replaced.

MAXIMUM DRIVE SHAFT RUNOUT: 0.02 mm (0.0008 in) 2.

5-9

Check the drive shaft for cracks or worn splines, and replace it, as required.

V-BLOCK DRIVE SHAFT

ASSEMBLY NOTE: _______________________ Always use new gaskets, oil seals and 0-rings.

The use of any used oil seal or 0-ring may result in oil leakage due to invisible scratches or stretches. Apply grease to parts where specified.

1.

Drive shaft bushing Using the bushing installer (YB-6029), install the bushing.

a. Remove the bushing support from the center bolt, and insert the center bolt into the lower casing from its top. b. Insert the bushing into the center bolt from the gear case side, and lock the bushing support. c. While locking the center bolt, screw in the nut (clockwise). d. Likewise, install other bushings.

1. Center bolt

2. Bushing support

2.

Bearing and oil seals Using the handle (YB-6071) and attachment, install the bearing and oil seals.

a. Propeller shaft bearing Install the bearing in the gear case so that the mark indicating the bearing size is on the exposed-to-view side. Install the attachment (YB6014) on the handle, and place it on the bearing so that it is at right angles to the bearing, then drive in the bearing.

3. Plate

5-10

NOTE: __________________________

b. Drive shaft oil seals Install the attachment (YB-6025) on the handle. Install the oil seal on the attachment, and fit it into the water pump housing cover. Next, fit the other oil seal into the lower casing.

Be sure that the oil seal lip is on the correct side. After installing the oil seals, pack their lips with grease (Yamaha all-purpose grease, P/N LUB-GREAS-13-00).

3.

Drive shaft, water pump, pinion and forward gear a. Align the mating surfaces of the insert cartridge and oil seal protector, and install them to the lower casing. b. Install the water pump housing cover, cartridge outer plate, impeller, and dowel pin on the drive shaft.

c. Propeller shaft oil seal Install the attachment (YB-6025) on the handle. Install the oil seal on the attachment, and fit it into the lower casing cap. cap.

c. Install the ge,ar adjust shim(s) (if required) and gear assembly (an assembly of forward gear and propeller shaft).

5-11

g. Apply Yamaha Bond No.4 to the water pump housing cover side of the cartridge outer plate. Then install the cartridge outer plate and water pump housing cover, and secure with two bolts.

d. Insert the drive shaft into the lower casing, and by turning the impeller (which is fitted to the drive shaft) clockwise, screw it into the insert cartridge. Before installing the impeller, grease it (Yamaha all-purpose grease, PIN LU BGREAS-13-00).

TIGHTENING TORQUE: M5 5.0 Nm (0.5 m ¡kg, 3.6 ft ¡lb) h. Install the water seal rubber to the water pump housing cover.

e. Install the gear adjust shim(s) (if required), washer, and pinion on the end of the drive shaft. Be sure that the pinion is correctly in mesh with the splined portion of the drive shaft.

5. Gear shim adjustment a. Gear backlash A clearance (called "backlash") is allowed between the two mating gears in order to take into account possible errors in machining, center-to-center distance tolerance, deformation due to load or thermal expansion and oil film thickness.

NOTE: ----------------------When mounting the washer on the drive shaft, it must be aligned with the groove in the gear case. f. Lower the drive shaft so that the dowel pin attached to the drive shaft fits in the groove in the impeller and at the same time, install the pinion on the end of the drive shaft.

After installing the pinion, lock it with the circlip.

GEAR BACKLASH: 0.08-0.3 mm (0.003-0.01 in)

5-12

Measurement Backlash=-----1.57

BACKLASH

b. Adjustment 1) Install the dial gauge on a magnetic base and the stand (YB-7003).

2) Install the lower casing cap on the gear case, and install the dial gauge stand on the cap.

3) Install the backlash indicator rod (YB-6265) on the propeller shaft, and set the dial gauge so its stem contacts the mark on the indicator rod.

GEAR ADJUST SHIM: 0.3 mm (0.01 in), 0.5 mm (0.02 in) 5) If the backlash is smaller than 0.08 mm (0.003 in), increase the shim thickness, and if larger than 0.3 mm (0.01 in), decrease the shim thickness.

If it is impossible to adjust the backlash to the range from 0.08 to 0.3 mm (0.003 to 0.01 in), the replacement of the gear or bearing may be required.

6) Lower casing cap Apply Yamaha Bond No. 4 to the lower casing cap gasket.

Secure the lower casing cap to the gear case with two bolts.

rod.

TIGHTENING TORQUE: M6 8.0 Nm (0.8 m ¡ kg, 5.8 ft ¡ lb)

1. Dial gauge stand 2. Dial gauge 3. Backlash indicator rod

4) Lock the drive shaft, and gently turn the propeller shaft in and out while pushing it downward.

When a click is felt, stop turning and read the maximum deflection .of the needle.

NOTE: ----------------------1. Lock the drive shaft tightly.

2. Do not turn the propeller shaft quickly, or the accurate measurement of gear backlash will be impossible.

5-13

INSTALLATION 1. Apply Yamaha all-purpose grease, P/N LUB-GREAS-13-00, to the joint area of the drive shaft and crankshaft.

2.

Install the upper ~asing gasket and Anti- I cavitation plate.

5. Remove .the gear case oil drain plug and oil level plug, and feed gear oil into the oil drain plug hole until oil flows out from the oil level hole. Don't feed oil into the oil level plug hole.

3.

Install the lower casing to the upper casing. Make sure that the drive shaft, water seal rubber and upper casing gasket firmly fit to the crankshaft, water tube and water pump housing. cover respectively, and tighten the two bolts securing the lower casing.

TIGHTENING TORQUE: M6 8.0 Nm (0.8 m ¡kg, 5.8 ft ¡lb) 4.

Install the shear pin to the propeller shaft, apply Yamaha all-purpose grease, P/N LUB-GREAS-13-0, to the shaft, and install the propeller. Insert the cotter pin into the holes. Bend the cotter pin ends.

5-14

CHAPTER 6 RECOIL STARTER DESCRIPTION ................................................. 6-1 REMOVAL ..................................................... 6-1 DISASSEMBLY ............................................... 6-1 INSPECTION AND REPAIR ................................ 6-3 Drive Pawl ...................................................... 6-3 Starter Rope .................................................... 6-3 Starter Housing Shaft ........................................... 6-3 Return Spring ................................................... 6-3 Drive Pawl Spring ........................................ ·...... 6-3 Sheave Drum ................................................... 6-4

ASSEMBLY .................................................... 6-4 INSTALLATION ..............................................

6-5

CHAPTER 6.

RECOIL STARTER DESCRIPTION

REMOVAL

The recoil starter consists mainly of the starter rope, sheave drum, starter spring, drive pawl and drive pawl spring.

The drive pawl connects the sheave drum with the flywheel, and the spiral spring rewinds the starter rope.

Remove the three starter assembly mounting bolts and then remove the starter assembly.

NOTE: _______________________ When the starter handle is pulled out, the starter spring works against it and therefore, the starter handle must not be released.

DISASSEMBLY 1. Turn the sheave drum so that the cut on the outer surface of the sheave drum faces toward the starter handle.

2. Pass the stater rope through the cut.

3. Turn the sheave drum clockwise until the starter spring is free.

1.

2.

3.

4.

5.

6.

7.

8.

9.

Starter handle Starter rope Return spring Drive pawl Drive pawl spring Starter housing shaft Sheave retainer bolt Sheave drum Starter spring

6-1

WARNING:

When removing the sheave drum, be sure to set the spring free and remove the sheave retainer bolt. Otherwise, the starter spring may fly out and cause injury.

4.

Remove the bolt at the center of the starter case and then remove the sheave drum from the starter case. When removing the sheave drum, hold down the starter spring with a screwdriver inserted into the hole in the sheave drum so that the starter spring will not spring out.

1. Sheave retainer bolt 2. Drive pawl spring 3. Starter housing shaft

5.

Undo the knots in the rope for the starter handle and sheave drum. Then remove the rope.

6.

Holding the spring with one hand, unfold the spring from its center with the other.

Be careful the spring does not jump out.

WARNING:

When removing or installing the starter spring, use care not to injure your hand.

It is advisable to wear gloves.

4. Return spring 5. Drive pawl

6-2

INSPECTION AND REPAIR Drive Pawl Check the drive pawl for cracks, chips, excessive wear or other defects, and replace as required.

Starter Rope Check the starter rope for wear or breaks and replace as required.

WORN

BROKEN

STARTER ROPE LENGTH: 1.300 mm (52 in)

DRIVE PAWL

NOTE=----------------~----­ When replacing t~e starter rope, cut it to the specified length ( 1,300 mm or 52 in) and burn the rope end so that it will not unravel.

Starter Housing Shaft

Starter Spring Check the starter spring for distorted ends or breaks and replace as required.

If the shaft is bent extremely, correct the bend.

If cracked, replacement is necessary.

BROKEN

Q

BROKEN

.

STARTER SPRING

STARTER HOUSING SHAFT

Return Spring Check the return spring for bends or breaks and replace as required.

Drive Pawl Spring Check the drive . pawl spring for bends or breaks and replace as required.

BROKEN

BROKEN

RETURN SPRING

DRIVE PAWL SPRING

6-3

Sheave Drum Check the sheave:; drum forcracks, chips or other defects and replace as required.

CRACKED

2.

Insert the rope through the rope hole and knot the end.

3. Wind the rope two and a half turns counterclockwise onto the sheave drum.

4. Place the rope at the cutaway.

5. Position the inner end of the starter spring on the projection of the sheave drum.

SHEAVE DRUM

ASSEMBLY 1. Apply Yamaha all-purpose grease, PIN LUB-GREAS-13-00, to the inner surface of the starter case.

Hook the outer end of the starter spring onto the projection attached to the starter case and install the spring into the starter case by winding it c;:ounterclockwise.

A brand new starter spring is held in a steel hoop. To replace with a new one, hook its outer end on to the projection first, and put it into the starter case, then remove the steel hoop.

6. Apply Yamaha all-purpose, grease, P/N LUB-GREAS-13-00~ to the sheave drum, install the drive pawl and the return spring.

Next, fit the drive pawl spring over the starter housing shaft (boss), and bolt them to the starter case with the sheave retainer bolt.

Make sure the projection on the drive pawl is between both ends of the drive pawl spring.

7.

6-4

Push the rope through the guide hole in the starter housing and install the starter handle.

10.

Pull all remaining rope through the guide hole and slowly release the sheave drum so that all the rope is pulled back into the sheave drum.

11. Pull out the stater rope, and check that it does not bind the return spring.

INSTALLATION 8.

Wind the spring up counterclockwise until tight.

9.

Slowly release the sheave drum one turn clockwise, and hold it at this point.

Secure the starter assembly to the power unit with three bolts.

6-5

CHAPTER 7. APPENDICES SPECIFICATIONS ............................................. 7-1 General Specifications .......................................... 7-1 Maintenance Specifications ..................................... 7-3

TIGHTENING TORQUE ...................................... 7-5 GENERAL TORQUE SPECIFICATIONS ................... 7-6 TROUBLESHOOTING ........................................ '1-7 EXPLODED DIAGRAMS ...................................

7-11

Electrical Component and Recoil Starter ...................... 7-11 Power Head ................................................... 7-12 Cowling and Fuel Section ................................... 7-13 Carburetor ..................................................... 7-14 Upper Casing Unit ............................................. 7-15 Lower Casing Unit ............................................. 7-16

FUEL AND AIR INTAKE SYSTEM ....................... 7-17 COOLING AND EXHAUST SYSTEM ..................... 7-17 WIRING DIAGRAM ......................................... 7-18

SPECIFICATIONS General Specifications el

2N

Item Dimensions: Overall length Overall width Overall height Transom height (Boat transom) Weight Performance: Full throttle operating range Maximum output ...... *1 Maximum fuel consumption ...... *2 Engine: Engine type Number of cylinders Total piston displacement Bore and stroke Compression ratio Intake system Scavenging system Exhaust system Lubrication system Cooling system Starting system Ignition system Spark plug Plug gap Carburetor starting system Bracket: Tilt position Trim angle Tilt-up angle Fuel and oil: Fuel Mixing ratio (gas & oil) Gear oil type Gear oil quantity Fuel tank capacity

400mm (15.8in) 185mm ( 7.3in) 920mm (36.2in) 381 mm (15.0in) 9.9 kg (21.81b)

4,000 r I min - 5,000 r I min 1.5 kW (2.0 ps)/5,000 r/min 1.25 L/H (0.33 Us gal/H)

2-Stroke 1 43 cm 3 (2.6 cu. in.)

39mm x36mm (1.54in x 1.42in) 7.4 Reed valve Schnurle Under water Pre-mixed gasoline and Oil Water Recoil starter Flywheel magneto B-5HS (NGK) 0.5mm -0.6mm (0.020-0.024in) Choke type

4 0째,4째,8째,12째

no

Pre-mixed gasoline and Oil 100:1(1%) Yamaha gear case lube 45 cm 3 (1.5 Us oz) 1.2 L (0.3 Us gal)

7-1

Item

~I

2N

Drive unit: Gear ratio Reduction system Turning direction of propeller Propeller drive system

2.08(27/13) Spiral bevel gear Clockwise Shear pin

Propeller: Number of blades x Diameter x Pitch-Type of bush

*3 Remarks: The data indicated by * 1 is propeller shaft horse power.

Fuel consumption *2 varies according to boat type and load.

The propeller marked with *3 is made of plastics.

Specifications are subject to change without prior notice.

7-2

3 x 7 1/ 4 in x 4 '/,in - A 3 x 7 1/ 4 in x 5 in - A 3 x 7 1/ 4 in x 5 '/,in - A 3 x 7 'I. in x 4 in - A

.

Maintenance Specifications 1. Engine -----Item

Model

2N

-------

Cylnder head: Warp limit

0.1 mm (0.004 in) *Lines indicate straightedge measurement

Cylinder: Bore size Taper limit Out of round limit

0.08 mm (0.003 in) 0.05 mm (0.002 in)

Piston: Piston size/ Measuring point* Piston clearance Oversize 1st 2nd Offset

39-8.2mm (1.535-8.oo79in)/ 5.0mm (0.197in) 0.03-0.04 mm (0.0012-0.0016 in) 39.25mm (1.545in) 39.50mm (1.555in) 0

39~· 02 mm (1.535+8· 0008 in)

Piston ring:

."f.PP ring T

Sectional sketch

~ Plain

2nd ring T

~ Plain

B=2:8:~mm (0.079:8:8min) B=2:8:8~mm (0.079:8:8min) T=1.8±0 · 1 mm (0.071±0.0039in) T=1.8±0 · 1 mm (0.071±0 ·0039 in) 0.1 -0.3 mm (0.004- 0.012 in)

End gap (Installed)

0.03-0.07 mm (0.001 -0.003 in)

Side clearance Crankshaft:

-

D

Crank width "A" Run out limit "B" Connecting rod big end side clearance "C" Small end freeplay limit "D" Crankshaft bearing Type (Upper) Type (Lower) Oil seal Type (Upper) Type (Lower)

28:8:~8 mm ( 1.1 02:8:~ in) 0.02 mm (0.0008 in) 0.5:::S:~mm (0.020~8:~in) 2 mm (0.08 in) 86004 86302 SD-200-300-7 mm S D-150-420-8 mm

7-3

Carburetor: Stamped mark Main jet Needle jet Jet needle Cutaway Choke plate hole Main air jet Valve seat Float level Trolling speed

K #96 02.085 #071- 2 / 4 0.75 04 01 01.4 4±0.5mm (0.157±0.020inl 1,150 r/min -1,250 r/min

(M.J.I (N.J.) (J.N.I IC.A.I (C.P.H.I (M.A.J.I (V.S.I

Reed valve: Thickness* Valve lift Bending limit

0.15±0 ·02 mm (0.0059±0·0008 inl 6mm 0.3 mm (0.012 in)

2. Electrical el

2N

Item Ignition system: Ignition timing (B.T.D.C.I Contact breaker: Model/ Manufacturer Point gap Condenser: Model/ Manufacturer Capacity lngition coil: Model/ Manufacturer Minimum spark gap Primary winding resistance Secondary winding resistance Flywheel magneto: Model/ Manufacturer

Flywheel magneto 18° ±1

- /MITSUBISHI 0.35mm (0.014in) F315T03971/ MITSUBISHI 0.25p.F ± 10% at 20°C (68°F) F120X05871 I MITSUBISHI 0.8mm (0.031 in) 1.060±10% at 20°C (68°FI 6.05k0± 10% at 20°C (68°F) F002T35071/MITSUBISHI

7-4

Lower casing unit

路~ 路-~路------2N-----------i i:Jrive shaft runout

: !".02 mrn (0.0008 in)

C( []

zs

II I

I

zs

Gear backlash Shim Forward gear Pinion gear Propeller shaft bearing Type Drive shaft oil seal Type (Upper) Type (lower) Propeller shaft oil seal Type

0.08-0.3 mm (0.003- 0.012 in) 0.3mm (0.012in), 0.5mm (0.020inl 0.3mm (0.012in), 0.5mm (0.020in) B6000 SW-110-210-8 mm SW-110-210-8 mm SW-100-210-10 mm

TIGHTENING TORQUE Tightening torque Part to be tightened

Part name

Thread size

Q'ty

Remarks Nm m路kg ft. lb

ENGINE: 1st

Bolt

M6P1.0

6

5

0.5

3.6

2nd

Bolt

M6P1.0

6

10

1.0

7.2

1st

Bolt

M4P1.0

4

5

0.5

3.6

2nd

Bolt

M4P1.0

4

10

1.0

7.2

1

20

2.0

14

1

44

4.4

32

Crankcase

Cylinder head Spark plug Flywheel

Nut

-

M12 P1.25

7-5

Apply Yamaha Bond No. 4

Apply LOC-TITE

GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard fasteners with standard I.S.O. pitch threads.

Torque specifications for special components or assemblies are included in the applicable sections of this book. To avoid warpage, tighten multi-fastener assemblies in a crisscross fashion, in progressive stages, until full torque is reached. Unless otherwise specified, torque specifications call for clean, dry threads. Components should be at room temperature.

A

8

(Nut)

(Bolt)

8 10 12 14 17

7-6

mm mm mm mm mm

M 5 M 6 M8 M10 M12

General torque specifications Nm

m¡kg

ft. lb

5.0 8.0 18 36 43

0.5.

3.6 5.8 13 25 31

0.8 1.8 3.6 4.3

TROUBLESHOOTING Engine does not start.

I FUEL JI----•There is no fuel in the carburetor.

• Fuel tank .................... Empty or fuel level is low.

• Fuel hoses ................... Leakage, Flattend, Broken • Fuel cock .................... Leakage, Broken, Clogged

......____ There is fuel in the carburetor.

• Fuel tank .................... Fuel is deteriorated or dirty.

I SPARK :1----•Spark is weak.

• Spark plug .................. Incorrect gap, Carbon deposit, Dirty, Oily or burnt • Plug cap .................... Faulty, No contact • Ignition coil .................. Defective • Contact breaker point ......... Not insulated, Not connected, Incorrect gap, Pitted, Burnt, Worn • Condenser ................... Weak, Shorted, Bad contact

...____ _• Spark is strong.

I•

I

COMPRESSION

Compression pressure ......... Incorrect

1~----•• Compression pressure is incorrect.

• • • •

Gasket ...................... Air leakage Oil seal ...................... Worn Reed valve .................. Broken Piston Cylinder wall ................. Worn, Broken, Scuffed Piston ring 7-7

Engine turns over but stalls.

Engine runs irregularly, stops or idles roughly.

l

FUEL

~1-------.

I SPARK :~----......

• Fuel tank .................... Fuel is deteriorated or dirty.

• Fuel hoses ................... Leakage, Bent, Kinked, Flattened, Broken • Fuel cock .................... Leakage, Broken, Clogged • Carburetor ................... Needle valve is worn.

Full-loosened adjust screw.

Choke is closed.

Water is in mixture.

• Spark plug .................. Spark is weak, Incorrect gap, Carbon deposits, Dirty, Oily or burnt • Contact breaker point ......... Not insulated, Not connected, Incorrect gap, Pitted, Burnt, Worn • Ignition timing ............... Incorrect ignition timing

I COMPRESSION I • • • •

Gasket ...................... Air leakage Oil seal ...................... Worn Reed valve .................. Broken Piston Cylinder wall ................. Worn, Broken, Scuffed Piston ring

7-8

Power loss

I

BOAT

1~-----

• Distribution of load ........... Improper load distribution, on boat Overload • Boat hull .................... Fouled with seaweeds and shells • Trim angle ................... Improper • Transom height .............. Low or high, Air draw, Cavitation

I LOWER UNIT

• Propeller .................... Bent, Broken, Loosely fit, Incorrect size • Water inlet .................. Clogged • Water pump ................. Worn, Broken • Water jacket ................. Clogged

I II----.

FUEL

• Fuel tank .................... Fuel is deteriorated or dirty.

• Fuel hoses ................... Leakage, Bent, Kinked, Flattened, Broken • Fuel cock .................... Leakage, Broken, Clogged • Carburetor ................... Needle valve is worn, Pilot passages are clogged, Water is in mixture, Choke is closed.

ISPARK If---•... • Spark plug .................. Spark is weak, Incorrect gap, Carbondeposits, Dirty, Oily or burnt • Ignition timing ............... Incorrect ignition timing

• • • •

Gasket . . . . . . . . . . . . . ........ Air leakage Oil seal . . . . . . . . . . . . . . . . . . Worn Reed valve .................. F<roken Piston Cylinder wall ................. Worn, Broken, Scuffed Piston ring

7-9

Engine misfires

IFirst check for spark to find cause. I I FUEL:~-----~-

I

SPARK

·

• Fuel tank .................... Fuel is deteriorated or dirty.

• Carburetor ................... Clogged

t-1--" •

·

Spark plug .................. Incorrect gap, Carbon deposits, Dirty, Oily or burnt • Plug cap .................... Broken or not tightly fitted • Ignition coil .................. Defective • Ignition timing ............... Incorrect ignition timing

7-10

EXPLODED DIAGRAMS Electrical Component and Recoil Starter GREASE: : Yamaha grease A (Water-resistant grease)

M6 8.0 Nm (0.8 m · kg, 5.8 ft ·I b)

SEALING AGENT: : Locking agent INEJI-LOCKI : Locking agent (LOC-TITEI : Yamaha Bond No. 4

M12 FLYWHEEL NUT 44 Nm (4.4 m • kg, 32 ft · I b) f - - - - - - - - J

I

I

8.0 Nm (0.8 m ·kg, 5.8 ft · lb)

M6

7-11

Power Head

CRANK 0.02 mm SHAFT 10.0008 ml _RUNOUT LIMIT·.

7-12

Cowling and Fuel Section

See to page 7-14

7-13

Carburetor

7-14

Upper Casing Unit

M6 8.0 Nm (0.8 m·k g. 5.8 ft . lb)

MS. 17.6 Nm (1.8m·k g. 12.6 ft. lb)

7-15

Lower Casing Unit ~---9

I LL:] ___~u_9 __~1~n~I_Ju --x2S

DRIVE SHAFT RUNOUT 0.02 mm IO:CXJOB in)

M5 4.4 Nm (0.45 m • kg, 3.2 ft · lbl

l

.

[:LD:t

..

~

~

.

..

.

.

IO"'IL'S:;;:E:-;;-AL;-------.

~ L-/1SW-11t/l-21ti>-8 mm

~

M& 8.0 Nm (0.8 m · kg, 5.8 ft · lbl lOlL SEAL SW-11tP-21t/l-8 mm

GEAR LASH 0.08- 0.3 mm 10.003- 0.012 in)

M& 8.0 Nm (0.8 m • kg, 5.8 ft • lbl

7-16