4000 Onan gen. Will not run

[OKpete]

Got ready to go on first short trip of season and generator would not run. Got it to start with no problem, however, it will only run for about 20 seconds and shuts down. The fault code is 3/6 which I believe is fuel not a computer problem. I did not run it a lot over winter but did have Stabil and Seafoam in gas tank. I have tried spraying carb cleaner in and starting fluid to try to clean out carb ( difficult to do in the small space in 317ODS) When it starts it sounds great. I am not a mechanic and dreding taking it to Camping World for service. Any suggestions would be appreciated.

[lbrunning]

check the little things first are you over a 1/4 full on gas does the fuel pump run when you push the stop/primer switch is the altitude adjustment setting in the right position. had a friend with same problem a few weeks ago and i took the cover off and switched the breaker off it took 3 or 4 tries running 20 seconds or so before it stayed running switched breaker back on and it was good to go. also check oil level

[OKpete]

Did try everything you mention, except breaker switch. I did flip it on and off one time to make sure it was on but I will try it a few more times. Thanks

[Kevin & Judy]

I would contact Onan and take it to them, They normally have the parts in stock and can sometimes get you out i a day. There are some dealers that can only change oil and filters on them not perform service work.

[SidecarFlip]

Just curious about some things. You said you used Stabil. Was it red Stabil or Blue Marine Formula. If it was Red Stabul, you had phase shifting of the e-gas in the carb and it's gunked up. Only Blue Marine Formula is good for the long term (over a month) and


When you put the Stabil in the tank (and Seafoam too) did you run the engine afterwards? If you didn't, you are out of luck, the carb needs to be removed and cleaned out.

[OKpete]

I have been thinking back and now believe I DID NOT run the gen after adding Stabil. I did not follow my usual procedure and will have to pay up. Thanks for the help.

[SidecarFlip]

I'm in the process of rebuilding 2 Honda Foreman 400 quads for a customer that he left the fuel sit in for a year.

When I pulled both carbs and removed the float bowls, both bowls were dry but the phase separated e-gas left behind plenty of corrosive evidence. Both jugs were clogged with white powdery crap and the bowls were growing what appeared to be brown mold. The the bottom of the bowls were severely corroded, jets were clogged and overall, both carbs were junk.

2 new carbs, an ignition coil, valve adjustment and oil change and filters and he's good again to the tune of 400 bucks and a warning from me on his bill..

If you must use e-gas, add Marine Stabil and run the engine to get it in the carbs. Then kill the engine, shut off the fuel and drain the float bowls and leave the drain screw out (put it in a safe place).

In lieu of e-gas, I always suggest non e-gas which is available at select stations for seasonal power equipment. With non R gas, the red Stabil is accepatble.

I've replaced a lot of gummed up, corroded carbs, rock hard fuel lines and fouled sxpark plugs from r-gas. Good for e, I get paid for it. Bad for you, you have to pay for it.

Don't be surprised if Onan installs a new carb. All one has to do is look in the float bowl to see how bad it is, or isn't.

[OKpete]

Thanks for the info, I knew better but had a brain bubble

[Secarider]

I have a 5500, just got back from local Cummings dealer, they ran my generator for 32 hours, I took it in because it would shut off after thirty seconds and 10 minutes, sporadic not every time.

Thirty two hours starting and stopping numerous ties in coach and on generator not once did it stop for the dealer. I started and stopped it several times coming home from dealer and no issues. I just wonder if I had gunk in carb, I never started it this winter or put seafoam in gas. Then again after shut downs this spring so far I would let it sit and it would start up and run for hours without issues.

I have no idea what it is. We will see next time we start it.

[santara]

DO not take to CW at all find somebody else

[SidecarFlip]

Originally Posted by santara

DO not take to CW at all find somebody else

Pretty much goes without saying. You always need an factory authorized dealer to work on something like a genny, not a high school trained parts replacer.

[SidecarFlip]

Originally Posted by Secarider

I have a 5500, just got back from local Cummings dealer, they ran my generator for 32 hours, I took it in because it would shut off after thirty seconds and 10 minutes, sporadic not every time.

Thirty two hours starting and stopping numerous ties in coach and on generator not once did it stop for the dealer. I started and stopped it several times coming home from dealer and no issues. I just wonder if I had gunk in carb, I never started it this winter or put seafoam in gas. Then again after shut downs this spring so far I would let it sit and it would start up and run for hours without issues.

I have no idea what it is. We will see next time we start it.

In the process of phase shifting, e-gas produces clumps of gunk and deteriorates fuel lines too. You could have a bit of fuel line floating inside the float bowl or a clog of gunk sporadically blocking a jet or emulsifying tube. Remember, the holes in them are tiny.

My SOP is always run the engines dry and then open the float bowl drains to get the rest out. I gave the quad carbs back to the owner (I always give a customer all the replaced parts back or I'd take a picture of the inside bottom of the float bowl(s). Amazing how much corrosion was inside.

I do that with my inverter genny too. Shut the fuel off, run the motor until she quits and the open the float bowl drain and leave the drain screw out (I tape it inside the genny cabinet). I still puy Marine Stabil in the fuel tank because just because the carb is dry and the fuel lines are empty, the gas is going to crap in the fuel tank anyway.

You get globs of crap in the fuel tank and turn on the fuel and go to start the genny and the crap flows down the fuel line and either clogs the fuel strainer of gets in the carb and then you have an issue.

Worst thing the government ever did was the ethanol mandate.

good for the aftermarket additive people, bad for an engine owner if it;s a seasonal engine.

[Garrette]

Check fuel pump.

[Wolverine 1945]

There is a video on-line showing how to check fuel pump & fuel filter,,, Utube I think !!!
I ran ours a couple of times this winter,,, it started & ran fine !!! Because I threw my back out in January I did not start it as many times as I wanted to !!!
Tried starting it a few weeks back,,, it would only run for 2 or 3 seconds !!! I did open the drain on the bottom of the carb bulb,,, did not get 1 drop of fuel !!! Primed the H out of it and opened drain again,,, still not a drop ???
I am guessing it is fuel pump or fuel filter,,, I can hear the pump running when I prime but no gas getting to the carb,,, I went on-line and found the closes ONAN service that could get us in this week,,, so on Wednesday we are off to ONAN of Grand Rapids,,, there is a large service center in IN but they were booker until June 28th !!!

[Patricia1968]

Be sure of the fuel it uses. Many new gens run off propane now.

[SidecarFlip]

Originally Posted by Wolverine 1945

There is a video on-line showing how to check fuel pump & fuel filter,,, Utube I think !!!
I ran ours a couple of times this winter,,, it started & ran fine !!! Because I threw my back out in January I did not start it as many times as I wanted to !!!
Tried starting it a few weeks back,,, it would only run for 2 or 3 seconds !!! I did open the drain on the bottom of the carb bulb,,, did not get 1 drop of fuel !!! Primed the H out of it and opened drain again,,, still not a drop ???
I am guessing it is fuel pump or fuel filter,,, I can hear the pump running when I prime but no gas getting to the carb,,, I went on-line and found the closes ONAN service that could get us in this week,,, so on Wednesday we are off to ONAN of Grand Rapids,,, there is a large service center in IN but they were booker until June 28th !!!

You mean the 'float bowl' not bulb....

Your fuel phase shifted and it's 'coagulated' in there. Clean out time (cheaper fix). New carb (more expensive).

Candidly, Marine Stabil (blue) works in your vehicle's fuel tank too. Just because the engine is fuel injected don't mean that Stabil will hurt it.

Sometimes I think there is a conspiracy going on between corn alcohol producers and carburetor manufacturers.

[Wolverine 1945]

Originally Posted by SidecarFlip

You mean the 'float bowl' not bulb....

Your fuel phase shifted and it's 'coagulated' in there. Clean out time (cheaper fix). New carb (more expensive).

Candidly, Marine Stabil (blue) works in your vehicle's fuel tank too. Just because the engine is fuel injected don't mean that Stabil will hurt it.

Sometimes I think there is a conspiracy going on between corn alcohol producers and carburetor manufacturers.

I know I should remove bowl and see if float is stuck,,, or try removing gas line and see if pump is working or if filter is plugged,,, not much room to work,,, and with my back like it is we decided to take it to a service center $$$ I am scheduled for a Spinal Injection next week to see if there is way to put off having a Fusion ??? Not sure it will help,,, but guess it is worth a try ??? Thanks sidecar for the advice !!!

PS: I did use Stable last fall,,, but not the Blue stuff !!!
I also see ONAN says to drain Fuel Bowl for storage !!!
ONAN says they do not rebuild carbs,,, because of there labor charges it is cheaper to replace the carb !!!

[SidecarFlip]

I just replaced 2 on 2 Honda quads. Did that because they were too far gone, internal corrosion from phase shifted fuel. Actually, a new carb won't be that much. Don't use RED STABIL, only the BLUE MARINE FORMULA. Red is fine for normal gas and e-gas for short term storage (month or less) but over a month, use Blue.

[Wolverine 1945]

Originally Posted by SidecarFlip

I just replaced 2 on 2 Honda quads. Did that because they were too far gone, internal corrosion from phase shifted fuel. Actually, a new carb won't be that much. Don't use RED STABIL, only the BLUE MARINE FORMULA. Red is fine for normal gas and e-gas for short term storage (month or less) but over a month, use Blue.

Our Genny has probably 3 hours on it,,, only used it once,,, other than running it from time to time,,, to try and keep it clean !!!

[Total Loss]

I have used red Stabil in all my stuff for years.
I still will get the occasional pilot jet minor clog.
My neighbors have been gone for 3 years and I have been keeping their still running 87 Camry running. Occasional red Stabil and have added a few gallons to keep it mixed with fresh fuel.
Still starts and runs. Octane is going though. I am amazed every time I start it up (once a month or so). But then it is a Toyota. Kind of an experiment for me.
3 years.