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Old 07-28-2019, 07:56 PM   #1
Join Date: Jun 2017
Location: North Georgia Mountains
Posts: 62
Loud Knocking Noise from Onan Generator when priming

Hey all,

Just a quick tip I discovered today:

Normally our Onan 4000QG generator on our class C coach is relatively quiet during the priming process, just before cranking to start it up. But today I was out at the storage, and when I tried to start the generator it wasn't a quiet priming process. instead, it made a loud, constant knock, knock, knock, knock noise. After checking forums and googling some similar concerns, I saw several references to a possible "no fuel" condition.

Finally, my brain put two and two together and looked at the gas gauge on the dash. It was down to 1/8th of a tank.

It was then that I remembered that my dealer told me that the generator only runs if there is more than 1/4 tank of fuel in the tank, to prevent you from becoming stranded by running the generator. What he didn't tell me though, was that you'll hear a very loud knocking noise from the generator fuel pump when that happens.

THAT is the troubleshooting tip I can offer today.

Stay safe and Happy Camping!
LeoS is offline   Reply With Quote

generator, noise, onan

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