Onan Gen--hard starting and surging

[RustyMacIntosh]

I was gifted a 95 Bounder 34ft with the big block Ford engine. 30kish miles. Sat a lot.

I've resurrected it back to 90% operational. I've made several statewide trips.

The generator. At first, it would not start. Now it starts after cranking maybe 30 seconds from the dash. It will start up, run for maybe 5 minutes then you can feel it begin to surge.

Opening up the side panel, it's running, smoother now that at first. But then it surges. It gets worse and worse surging, then quits. It might attempt to start again but dies like it is out of fuel.

Let it sit for several hours, it does the same routine, cranks (longer than I like), then fires up, smooth then begins to surge ultimately dies.

OK--the coach has gone thru maybe 10 tanks of gas. Including filters and treatment. The 460 runs nicely.

I was once told that this unit has a fuel pump. So far, I have not located it.

I can see the filter which is connected to the carb. I tried yesterday to remove the filter but was unable to get the brass connector to free up from the bottom of the filter. I'm going to try it again today with heavier tools.

I think it is running a bit rich. Or at least that is what the exhaust pipe looks like. I do not see any blue or black smoke from the exhaust.

I'm thinking that maybe its time to just swap in a new carb, a new filter and all. Fuel pump? I guess if I can find it.

Its the Onan 5000 model btw.

[ksg5000]

Most would agree that it's fuel related - likely gummed up carb and/or fuel filter or fuel pump. I would start with the gummed up carb since most rigs that sit have that in common. I would try the seafoam approach first - ain't fast but it's inexpensive and easy to apply. Small gas container with lots of seafoam can be connected to your fuel filter with small fuel hose - run the generator - let is sit - repeat.

[wildmanbaker]

Russ, your problem may be the fuel line from the tank to the gen. Get some fuel line the right size, and connect it to the inlet of the fuel pump. Then insert the other end in a container of gas of know quality, and start the generator to see if it will run. If it does, the fuel line from the tank to the metal line under the MH may have dried out and cracked, allowing air to enter the line causing the problems. It is possible to change the hose without dropping the tank, if you are not too muscled up.
Good luck

[rrupert]

Small engines and 10% ethanol gas are incompatible. The carburetor could be all gunked up as a result. It could require a rebuild or replacement to make things right. After taking care of the carb try to find a way to run the generator with ethanol-free gas and maybe your problem could go away.

[rockylarson]

You might find that filter below the carb has been discontinued. There is another on the fuel line just before the fuel pump on the lower backside.

[RustyMacIntosh]

OK...going to study this genset a bit more. Also get some Seafoam. I think maybe trying to get the cleaner to ungunk it first before I buy a carb. Looks like Ebay does have aftermarket models.

[DFord]

After years of setting the carburetor is probably gummed up. Replacing it may be the easiest fix. I've heard there are 3rd party carbs on eBay at reasonable prices. You'll need the model and serial and "spec" numbers of the generator to find the right part.

The fuel pump may be on the back side of the generator. The fuel line to the gas tank may have a crack allowing the fuel pump to suck air instead of gas after so many years. You can use a short piece of hose stuck in a gas can next to the generator bypassing the fuel line to see if that related to your problems.