Seafoam Treatment

More than likely a fuel delivery problem. Tell us what year your generator is. If it is 8-10 years old the rubber fuel hose from the gas tank is probably hardened and cracked and sucking air. That will give you the condition you describe.

RJsfishin wrote:
You don't have to crank the engine to check fuel flow.
The fuel pump is electric, and will run in the prime (off) position of the "start/stop" button

Gjac wrote:
I would disconnect the fuel line and crank the eng, does the fuel shoot out? If not disconnect the intake side of the line and suck on it then put your finger over it and see if it hold vacuum. I use a clear tube on the line to see the fuel. If your line is good and you get fuel out of the pump I would put the intake line into a gal of gas and a half can of Seafoam and run it for an hr under load after you flood the carb with Seafoam and let it sit per the instructions on the can.

I don't have prime on mine.

You don't have to crank the engine to check fuel flow.
The fuel pump is electric, and will run in the prime (off) position of the "start/stop" button

Gjac wrote:
I would disconnect the fuel line and crank the eng, does the fuel shoot out? If not disconnect the intake side of the line and suck on it then put your finger over it and see if it hold vacuum. I use a clear tube on the line to see the fuel. If your line is good and you get fuel out of the pump I would put the intake line into a gal of gas and a half can of Seafoam and run it for an hr under load after you flood the carb with Seafoam and let it sit per the instructions on the can.

How old is the gas?

I have cleaned up several gunked up carbs with Seafoam over the years. YMMV, but what I generally do for a engine that will not stay running is get it running on the spray for a minute, then FLOOD the engine forcing it to shut down. Let it sit for a few hours, then repeat. When it will run on its own I add Seafoam to the fuel and run it through.

I would disconnect the fuel line and crank the eng, does the fuel shoot out? If not disconnect the intake side of the line and suck on it then put your finger over it and see if it hold vacuum. I use a clear tube on the line to see the fuel. If your line is good and you get fuel out of the pump I would put the intake line into a gal of gas and a half can of Seafoam and run it for an hr under load after you flood the carb with Seafoam and let it sit per the instructions on the can.

We Cant Wait wrote:
If you have a good fuel flow to the carb, then yes it's a carb issue.

X2

I just went through this same thing two months ago then had my fuel pump go out on me.

It's definitely a fuel related issue. I'm not familiar with the Onan so bear with me here.

Remove the carb drain plug, or open the fuel drain screw. This will be on the bottom of the float bowl. A drain screw would be near a port or hose leaving the bottom of the float bowl. With the drain removed, you should have fuel pouring out since you've already established a good fuel supply to the carb.

If fuel is not coming out of the drain, you have a stuck float valve. You may be able to reach in through the drain hole and tap the float, but be careful to not press hard or the float level could be altered. Or remove the float bowl completely (probably require carb removal) and try to exercise the float to dislodge the float valve.

Quote:
could be a bad fuel pump, or clogged filter
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What part of quote:
"its being presented in a continuous flow" don't you understand?

If you can get to the fuel line, try and run pure Seafoam into the carb, then let it set for 24-48 hours. That will usually clear up any carb varnish problem.