TROUBLESHOOTING 29 Loud grinding noises when starter runs This can be caused by improper meshing of the starter pinion and flywheel ring gear or by a broken overrunning clutch mechanism. 1. Remove the starter. See Chapter Nine. 2. Check the starter pinion gear. If the teeth are chipped or worn, inspect the flywheel ring gear for the same prob- lem. Replace the starter and/or ring gear as required. 3. If the pinion gear is in good condition, the overrunning clutch mechanism in the starter may be defective. Replace the starter with a new or rebuilt marine unit.
Ammeter ~ - + Voltmeter ~ + - Solenoid (S) terminal + 12 volt battery Starter motor Starter Solenoid Resistance Tests Check the starter solenoid using the following resis- tance tests: CAUTION Disconnect the negative battery cable be- fore performing resistance tests. open circuit or a loose connection. If the engine does not start, replace the starter solenoid. I. Refer to Figure 2 and connect an ohmmeter lead to the S terminal of the solenoid. Connect the remaining ohm- meter lead to the metal body of the solenoid. The ohmme- ter should indicate approximately one ohm or less. Replace the solenoid if the ohmmeter indicates infinite re- sistance (no continuity). 2.
Refer to Figure 3 and connect an ohmmeter lead to the S terminal of the solenoid. Connect the remaining ohm- meter lead to the M terminal of the solenoid. The ohmme- ter should indicate approximately one ohm or less. Replace the solenoid ifthe ohmmeter indicates infinite re- sistance (no continuity). Starter spins but does not rotate flywheel 1. Remove the starter. See Chapter Nine. 2. Check the starter pinion gear. If the teeth are chipped or worn, inspect the flywheel ring gear for the same prob- lem. Replace the starter and/or ring gear as required. 3. If the pinion gear is in good condition, disassemble the starter and check the armature shaft for corrosion.
See Brush Replacement, Chapter Nine, for the disassembly procedure. If no corrosion is found, the starter drive mech- anism is slipping. Replace the starter with a new or rebuilt marine unit. Starter Motor No-Load Current Draw Test Starter will not disengage when start switch is released If troubleshooting indicates that the starter motor may be defective, use the following starter motor no-load cur- rent draw test to determine if the starter motor is in accept- able operating condition. To perform the test, the following equipment is needed: an ammeter capable of measuring 0-100 amps, a voltme- ter, a vibration tachometer and a fully charged 12-volt bat- tery.
Minimum battery capacity is 70 amp-hours for one- and two-cylinder engines and 100 amp-hours for three-cylinder engines. 1. Remove the starter motor from the engine. Securely fasten the motor in a vise or other suitable holding fixture. 2. Using a heavy gauge jumper cable, connect the amme- ter in series with the positive battery terminal (Figure 4). Connect a voltmeter to the battery. This problem is usually caused by a sticking solenoid or defective start switch, but the pinion may jam on the fly- wheel ring gear on an engine with many hours of opera- tion.
NOTE A low battery or loose or corroded battery connections can also cause the starter to re- main engaged with the flywheel ring gear. Low voltage at the starter can cause the contacts inside the solenoid to chatter and weld together, resulting in the solenoid sticking in the ON position.