ENGINE - 17 HP BRIGGS & STRATTON TESTS AND ADJUSTMENTS 5. Remove air cleaner element from engine so you can listen for air leaks through carburetor input (B). 6. Use flywheel mounting cap screw to turn flywheel and find approximate top dead center (TDC) of the compression stroke by removing spark plug and using a wooden dowel on top of piston.
B
7. Ground ignition high tension lead (C) using JDM-74A-5 Ignition Test Plug to protect ignition system and install test kit adapter hose into spark plug hole.
D
E
G
F MX9746 M85623
8. First turn regulator knob (D) on tester OFF (fully counterclockwise) then attach appropriate air source to coupler below black regulator valve.
10.Connect adapter hose (F) to tester. Watch and record gauge reading while listening for excessive air leaks at carburetor intake (B), and exhaust outlet (G). Pressure should hold steady or reduce only slightly.
9. Gradually turn regulator knob clockwise until needle aligns with “zero” of the yellow “SET” scale (E).
11.Remove test equipment and install spark plug. Tighten spark plug to 20 N•m (180 lb-in.).
c CAUTION: Avoid injury! Before attaching
adapter hose (F) hose to tester, make sure another person is holding on tight to breaker bar in top dead center (TDC) position. When compressed air is applied, there will be considerable torque forcing piston and crankshaft to turn.
12.Install hood. Results: Leakage should not exceed 25%; if so, listening at the carburetor (intake valve), oil filler (piston rings) or muffler (exhaust valve) for escaping air will provide clues as to where to investigate for problems. Air Leaks - Carburetor: slight . . . . . . . . “low-to-moderate” wear to intake valve excessive . . . . . . . . . . . .intake valve bad, fix or replace Air Leaks - Exhaust Outlet: slight . . . . . . . . “low-to-moderate” wear to intake valve excessive . . . . . . . . . . exhaust valve bad, fix or replace Gauge Color Codes: Green (low) . . . . . . . . . . . . . . . . . . . . .compression good Yellow (moderate) . . . . . . . . . . compression borderline Red (high) . . . . . . . . . . . . . . . . . . . . . . . compression bad
ENGINE - 17 HP BRIGGS & STRATTON Tests and Adjustments - 27 www.monstermanuals.com