Onan Geneator

goufgators wrote:
My Onan 5500 generator - gas has been cutting off after running 15 to 20 minutes. It always starts right back up but then (again) stopping after running a few minutes. I don't have a clue regarding where to start looking for the problem or if I need to just take to a repair shop. Any ideas, thoughts, suggestions?? Thanks! / Larry

P.S. / the MH is not low on gas...full tank!

I'm going out right now to check the oil level

goufgators wrote:
My Onan 5500 generator - gas has been cutting off after running 15 to 20 minutes. It always starts right back up but then (again) stopping after running a few minutes. I don't have a clue regarding where to start looking for the problem or if I need to just take to a repair shop. Any ideas, thoughts, suggestions?? Thanks! / Larry

Doesn't sound like a fuel supply problem, but you might try using a jug full of gasoline for test running it on, just in case a pin hole air leak is present in the rubber hose line going to the tank that gets worse with the flow of fuel going through.
Also be sure that you have the proper oil level. Then use a wiring diagram to find and disconnect the oil level safety switch, which could be bad. Also the oil temp. switch, if it has one and have found it to be the culprit on Generac units. This is a good bet and considering that it initially runs for as much as 20 minutes.

You might try removing the air filter and tapping it to remove any dust. Worked once for me.

We had "cut out" issues with our generator. Several people on this forum suggested the oil level was the issue. We took advice and have overfilled by a little bit. That has done the trick for us!

I do what Tropical suggested and add some seafoam every other year or when ever it gets hard to start. Another thing that I found is that a failing coil will open up and not produce spark once it gets hot. I would run it in a gal can of gas and 4 ozs of Seafoam it stops after 20 mins immediately check to see if you have spark. If it continues to run fine, check your hose to the gas tank. You can blow into the hose to clear any blockage and hear bubbles when it is open, then put a clear plastic hose on top of the black hose and suck gas up into the clear hose, block the end, and see how fast the level drops down. If you see the level dropping you probably have a rotting pick up hose. I had a failing connection where the PO replaced the fuel pump that would cause the genset to shut down also so look at the electrical connections going to the fuel pump..

When my 10K onan did that it turned out to be a loose fan belt and it was shutting down on overheat. Exact same behavior.

I had a problem similar to that . Mine was an electrical issue. My converter was not putting out 12 volts. Generator would run then for no reason fall off line. You could restart it it would run then again fall off line. Finally found a bad converter. Generator runs fine now. Just something to check if not a fuel issue.

Have you checked the generator start switch for error codes? A code can help sometimes.

Loose electric connection, low oil, pin hole leak in fuel line, maybe fuel filter. You might try jumping the oil sending sensor - should rule that out.

On ours it was the fuel pump.

Dave