Onan 5500 generator won’t turn over/crank

[Daniel Jay]

I cannot figure out why the generator won’t crank. There is no power to the generator from the house batteries. I have checked the batteries and they are good, connections are good. I am getting 13.7 volts on the batteries. The circuit breaker has power going through it. What else could I check? I am stumped. I have a 2018 precept 31ul.

[Parrott]

Have you tried the switch mounted on the generator itself?

[Daniel Jay]

Yes I did. There is no power to it from house batteries.

[Parrott]

Maybe try starting it with the booster switch on.

[Parrott]

Can you hear the fuel pump priming when you push the stop button? Easier to hear starting from the generator.

[JimD]

What circuit breaker are you measuring the 12 volts at? Is it the one inside the generator?

I would check the 12 volts inside the generator at the breaker. If you read it on both sides of the breaker (maybe this is what you were talking about) I would verify that ground is actually getting to the generator. If you measure 12 volts from the breaker to metal ground you should verify that the ground is indeed connected inside the generator wherever it connects.

If the 12 volts (positive and ground) are both OK inside the generator but yet it won't crank, I would measure for 12 volts on the starter solenoid. Should be constant on one of the large lugs.

If you get no 12 volts at all in the generator, I believe it is connected to the house batteries through a single large cable. Maybe there is a high amperage fuse/breaker inline with the cable.