POWERBOATER’S GUIDE TO ELECTRICAL SYSTEMS
Starter-Motor Problems and Solutions Because engine makers all use similar engine blocks and parts, starter-motor circuits have many similarities from one brand of engine to another. Therefore, I have been able to develop a generic procedure for troubleshooting and repairing them. However, the specifics for your boat’s engine can only be found in your workshop manual. Use the procedures in this chapter as a detailed guide to get you started in the right direction for locating and correcting specific problems. I will try to direct you to sections of your workshop manual when they are needed. The illustrations that follow show the major parts of the most common starter-motor circuits. Figure 8-1 shows a typical OMC/Volvo Penta starter circuit with all the important parts mentioned in the list that follows. Figure 8-2 on page 125 shows a typical MerCruiser starter circuit.
Remote Control
Ignition Switch
Starter Motor Solenoid Circuit Breakers
Basic Diagnostics
Starter Relay
There are five basic symptoms of starter-motor and starter-circuit problems, and basic diagnostics. Let’s look at the symptoms first, and we’ll explore each in detail in the next sections.
The starter motor is lethargic and turns the engine slowly. First check the condition of the battery and cable connections; then check the engine and reverse gear assembly to be certain they are not bound up. If these check out OK, make sure the cable connections at the starter motor are tight and clean. Finally, if all the wiring and the engine itself seem to be in good order, the starter motor itself is the likely culprit.
The starter motor doesn’t turn, but the solenoid makes a clicking sound. Check the battery and connections, the solenoid, the engine and drive for seizure, and finally the starter motor itself.
124
Fig. 8-1. OMC/Volvo Penta starter-motor circuit.
The starter motor doesn’t turn and the solenoid makes no clicking sound. Make sure the remoteshift lever is in neutral; then check the battery and connections, all fuses and circuit breakers, and the starter-motor solenoid.
The starter motor turns intermittently. Check the terminals at the ignition switch, the ignition switch itself, the neutral safety switch, the enginemounted slave solenoid or relay, and finally the starter motor itself.
Battery
The starter motor remains engaged and runs with the engine. Check for a faulty or shorted ignition switch, a faulty solenoid, or a faulty starter motor.
This list should make it clear that the most common cause of all the starter problems, except for a starter motor that remains engaged with the engine running, is found in the battery and cable connections. This cannot be emphasized enough. A battery
