Onan 4000 Gen Set Service

[71_340]

Attached is the page from my generator owners manual, outlining the oil check procedure. I have a 5500 generator though, maybe it is different.

our last Class C had a 3200 QD diesel generator which had a real dip stick, a much better solution.

[musichick3]

My generator stopped working when I ran low on gas in my 2018 Thor Freedom Elite, 22ft. I filled up my gas tank and it wouldn’t start. I checked and changed the oil in the generator because it was la little low and it was time anyway. Still wouldn’t start. I primed, waited, primed, and checked the black fuel line tube at the connection on the front of generator to make sure gas was getting through, which it was. I even got Seafoam and treated some new gas, disconnected and pinched off the fuel line to the main gas tank, per a you tube video, and primed it like it showed.
Still won’t start. It cranks but will not turn over. The spark plug is only a year old and wasn’t running rough before.
I checked the air filter and it looks clean. Is there something I’m missing here? The Generator is only a year old due to an accident that damaged tge original, so it shouldn’t need new parts, right? I haven’t used it that much either, so no high hours either. I’m stumped! 🤔

[Scubawise]

I would call Cummings they are very good on the phone

[musichick3]

Thanks!

[Scubawise]

Originally Posted by musichick3

Thanks!

Here is info

[16ACE27]

Originally Posted by musichick3

My generator stopped working when I ran low on gas in my 2018 Thor Freedom Elite, 22ft. I filled up my gas tank and it wouldn’t start. I checked and changed the oil in the generator because it was la little low and it was time anyway. Still wouldn’t start. I primed, waited, primed, and checked the black fuel line tube at the connection on the front of generator to make sure gas was getting through, which it was. I even got Seafoam and treated some new gas, disconnected and pinched off the fuel line to the main gas tank, per a you tube video, and primed it like it showed.
Still won’t start. It cranks but will not turn over. The spark plug is only a year old and wasn’t running rough before.
I checked the air filter and it looks clean. Is there something I’m missing here? The Generator is only a year old due to an accident that damaged tge original, so it shouldn’t need new parts, right? I haven’t used it that much either, so no high hours either. I’m stumped! 🤔

Did you check for spark? I would have verified spark long before doing all that extra fuel work once I knew fuel was getting to the carb.

[Chateau_Nomad]

Once you understand "suck, squeeze, bang, blow" it gives you pretty clear insight for troubleshooting small engines!

[musichick3]

Originally Posted by Chateau_Nomad

Once you understand "suck, squeeze, bang, blow" it gives you pretty clear insight for troubleshooting small engines!

Can you explain that for me? 😄

[musichick3]

Originally Posted by 16ACE27

Did you check for spark? I would have verified spark long before doing all that extra fuel work once I knew fuel was getting to the carb.

I just read about doing that last night. I plan to do that today. Thanks for the tip!��

[MJC62]

Originally Posted by musichick3

Can you explain that for me? ��

I believe the Nomad is describing the way an internal combustion engine works though in terms my old high school auto mechanics teacher would have cringed at.
A 4 stroke internal combustion engine needs four functions to run. Intake, Compression, Power and Exhaust
1) as the engine turns over the piston goes down on the first cycle or stroke creating a vacuum & the intake valve opens to draw the air fuel mixture into the combustion chamber.(Intake)
2) the piston moves upward on the second cycle or stroke and compresses the air/fuel mixture. Both valves are closed (compression)
3) As the piston forces the compressed air/fuel mixture to the top on the 3rd cycle the spark plug fires and ignites the mixture pushing the piston down
(power stroke)
4) on the next cycle back up the exhaust valve opens and expels the spent gasses (exhaust) then the cycle begins again as the piston goes back down drawing in the air/fuel mixture eliminate any one of the 4 strokes and the engine won't run.
The usual suspects for an engine not starting are no spark or no fuel. As u have checked out the no fuel logically next step is to see if it has spark

[MJC62]

After U check for spark. If it has spark I would check to see if the gas is actually getting into the engine. When you prime the engine can you actually smell the fuel? You say U have fuel up to the carb so if the engine was running before the fuel ran low there is a possibility the carburetor float is stuck closed.