Help! Yanmar 2gm start not engaging

[sirlandsalot]

Hi, my generator 2gm starter periodically does not engage the motor. I can hear the starter turning, however the engine does not crank. After a few tries it cranks. I have already cleaned terminals and have new wiring.

Cheers

[SVHarmonie]

There are two possibilities.

On the starter motor there is a gear that moves out on the shaft to engage the flywheel and turn the engine. This can happen either with a lever attached to the solenoid, or with a centrifugal system sometimes called a "bendix drive". These systems can get sticky and work intermittently. Pull the starter motor, clean and lubricate the shaft and gear mechanism. If something is broken, a rebuild of the starter will get it working smoothly again.

The other possibility (the nasty one) is that there are teeth damaged or missing on the flywheel and there is nothing for the starter to engage at some rotational positions.

I hope your problem is the first one...

[Wotname]

There is a third possibility - not enough volts at the starter motor due to either not enough volts in the battery or resistance in the circuit.

Cleaning the terminals and new wire is good starting point but have you checked the negative return terminals (on the engine and back to the battery) and the voltage drop across the solenoid contacts.

As easy check is to measure the voltage right at the switched side of the solenoid and the starter motor case while cranking. It should be greater than 10V.