©eBlue-Dist 2007
TROUBLESHOOTING AND TESTING
Perform this test after performing a normal tune-up and synchronizing the ignitiontiming and carburetor. Refer to Chapter Five. Perform tests with the engine in the water, running at operating temperature in forward gear and with the tachometer installed. 1. Verify that the engine water pressure and oil level are at their normal range and that the engine is at normal operating temperature. 2. Disconnect the speed limiter blacWyellow wires from the CDI unit. See Figure 42 and Figure 43. 3. Start the engine and run it at approximately one half of its maximum recommended engine speed to determine if the misfire is still present. a. If the engine runs properly with the speed limiter circuit disabled, reconnect the speed limiting system blacWyellow wires and continue at Step 4. b. If the misfire is still present, the cause is not the speed limiter system. Test the ignition system as described in this chapter. 4A. 40-90 hp-If the engine runs correctly with the speed limiting circuit disabled, disconnect the water pressure sensor (1, Figure 42) and start the engine. If the engine now runs correctly, replace the water pressure sensor. If the engine still misfires, reconnect the water pressure sensor and disconnect the overheat sensor (2, Figure 42). Start the engine. If the engine now runs correctly, replace the overheat sensor. If the engine still misfires, continue at Step 5. 4B. 115-140 hp-If the engine runs correctly with the speed limiting circuit disabled, disconnect the water pressure sensor (1, Figure 43) and start the engine. If the engine now runs correctly, replace the water pressure sensor. If not, reconnect the water pressure sensor and disconnect the lower float (21, Figure 43) on the oil level sensor. If the engine now runs correctly, replace the oil level sensor. If the engine still misfires, continue at Step 5. 5. Disconnect the speed limiter input wires. See Figure 42 (40-90 hp) or Figure 43 (115-140 hp). 6. Start the engine. If the engine now runs correctly, replace the wiring harness. See 13, Figure 42 (40-90 hp) or 16, Figure 43 (1 15-140 hp). 7. If the engine still misfires, replace the CDI unit as described in Chapter Seven.
Speed Limit System Test Perform this test if the engine has a high-speed misfire. The excessive speed limit system prevents excessive speed by intempting the ignition at a predetermined engine speed. The CDI unit controls the system.
NOTE When the speed limit system activates, the ignition is interrztpted to prevent damage to the engine. The engine will over-speed and activate the speed limit system if the engine is under.-propped. Make ssue the cor*iAect propeller is used. Perform this test with the outboard motor mounted on a boat, in the water, in FORWARD gear. Make sure the engine is running at normal operating temperature and all synchronization and adjustment procedures have been performed. 1. Disconnect the speed limiter jumper. See Figure 42 and Figure 43. 2. Start the engine and run at the speed in which the misfire occurs. If the engine now runs correctly, replace the CDI unit as described in Chapter Seven. If the engine continues to misfire, the problem is not the speed limit system. Check the spark plugs and all other ignition components as described in this chapter.
Low-Speed Limit (115-140 hp) The low-speed limit circuit will prevent engine speed from exceeding 1500 rpm. If the engine will not accelerate beyond 1500 lpm, make sure the redlyellow wire (3, Figure 44) is in good condition and is securely connected to the CDI unit and remote control box. If the wire and connections are in acceptable condition, replace the CDI unit as described in Chapter Seven.
TRIM SYSTEM Tilt Pin and Lockdown Hook The trim and tilt systems used vary by model and horsepower. A tilt pin and hold-down hook (Figure 45) are used on 5-40 hp models. It allows the engine to run slightly tilted in or out to change the running attitude of the boat or to enhance shallow water operation. The hold-down hook operates when in reverse gear to prevent the propeller thrust from moving the engine outward. If the unit does not hold down when in reverse or cannot tilt up when in forward or neutral, check the adjustment and inspect the system for broken or excessively worn components. See Chapter Eleven for repair procedures and adjustments for these components.
