Forum Discussion

Bucktooth_Bucky's avatar
Jan 16, 2021

Onan 7500 generator wont start in cold

The problem with my generator:

It wont start in cold weather. It will start when it warms up
I push down the start button and you can hear it clicking as it should, but after that nothing.
Yesterday I put my torpedo heater under the rig and deflected the heat under the generator and warmed it up and it started:)
Now this morning at 32degreesF it wont start. Just the clicking

Any ideas?
  • Thought those had a cold start system? I think you hold down the switch in the opposite direction until the light blinks... Then try starting.
  • Sounds like your start battery is near dead. Thus you only get clicking when it's cold out.
  • The clicking is the glow plugs warming not a low battery clicking. I’ll try holding the switch in the stop position
  • What generator? Have you read the manual? If it's an Onan I think you do hold the stop for a few seconds to warm up the glow plugs.
    However, even without preheating it should still crank. The no cranking when cold sounds like a dead battery. Was your heater also blowing on the generator starting battery?
  • No heat was blowing on the battery. Battery is in back generator is in front under front seats. I’m plugged into shore power so batteries are showing 13-14v. FYI this is an onan 7500quiet diesel The rv is a 2003 fleet wood discovery
  • I cleaned the ground and the positive cables also. Im thinking that maybe the glow plugs are not heating up??? And this tells some sensor not to let the engine turn over. But I really have no idea
  • I just had somewhat the same problem. My Onan 8000 diesel would not start. I would hold down the stop button to heat glow plug then the start button. Nothing would happen other than I would hear the fuel pump working. I cleaned everything looked at everything. My RV tech told me to start the engine let it run for 30 min or so then try and start the gen.. Sure enough the gen started.

    I also was plugged in but found out the coach batteries were no good. The volts would read 13.5+/- so I thought all was ok. Took batteries out and had them tested the volts were good but the amps were not there to do much of anything. I learned its the amps that to the work.

    Just another note the gen also started with the motor running and the coach batteries disconnected. Get batteries checked

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,188 PostsLatest Activity: Jan 17, 2025