Onan 4000 gas generator shut down 3-6 code

[gymracer]

Not read all post but I had a 4000 has that started doing same thing when it was really hot...90. After fooling with it a couple of times, replaced fuel pump, fixed.

[Boiler01]

Originally Posted by gymracer

Not read all post but I had a 4000 has that started doing same thing when it was really hot...90. After fooling with it a couple of times, replaced fuel pump, fixed.

Thanks everyone for the responses. I was able to trace the fuel line back and it was pinched under a corner of the black tank. This weekend will be hot here (mid 90s) so I intend to test it out.

I also bought a new fuel pump and filter to try that if it continues to fail (very few hours on a brand new (1 year old, but was doing it from about 12 hours on the Genny) Genny/rig shouldn't require it but I have heard they can be problematic).

[Boiler01]

I tested my Genny last weekend in 94 degree heat after finding the fuel line was partially compressed under a corner of my black tank. It ran by itself for about an hour and a half, I then idled the engine with the genny on for another 30 minutes and then. I drove it to fill with gas (about 20 minutes each way) and when I was backing it up to put it away, the Genny shut off again. Same code 3-6. I have a replacement fuel filter and pump that I will change out this weekend. Really frustrating issue with a new rig...

[Nrabel]

My 4000 does this when it’s hot out. Recently the control board melted and looks like it lit on fire when it was cold and rainy though so there are some issues. Jayco really doesn’t care and told me to bring it to Onan. Hopefully they can resolve the 3-6 and the fire hazard. I’ll attach my pre and post control board pics.

[Boiler01]

Just replaced the fuel filter and pump on the 5500. Ran it in 90+ degree heat, direct sun for a few hours and everything checked ok. The real test will be later this month on our next trip.

[gymracer]

I had a 4000 gas and when really hot,90+ after about 8 hours it would shout off. Let it set hour or so and it would start but not run too long. At night when cooler it ran. I put a fuel pump on it and fixed it.

[Boiler01]

So just finished up a trip across the southern states and after replacing the fuel filter and pump, the genny stayed on while moving, but after getting into stop and go traffic, it still shuts itself off with the 3-6 code. If I wait to restart it for about 20-30 minutes it will come back on and run while in motion, but shuts off immediately when I encounter traffic again. The only other thing I have to go on is the plenum, but I am not confident it will help...I think it is a poor design to have the genny so close to the engine which causes an overheating issue when idling in high temps. I did check my board and there are no visible burn marks or melting like one of the other posters here, so I guess that is good?

As mentioned earlier I have the 5500 (i put the wrong model in the original thread title and do t see how to change it).

[4star]

Code 36. Tried all the fixes including heat sleeves on fuel lines, adding fuel pump close to the tank, lower oil level, higher oil level. What fixed it was re-routing the fuel line at the generator, right across the top of the generator, not behind it like from factory. Fuel was vaporizing in the line in the factory location which is extremely hot when driving. I've been trying for several weeks to keep it running in 90+ Temps. Finally was able to get it solved today while driving. Got it to shut down, then proceeded to troubleshoot in a parking lot. No fuel at bowl. Even holding down prime button. Cut fuel line about 4 feet behind generator (i dont recommend doing this lol). Plenty of pressure and fuel there. Rigged up new line above generator, bypassing factory line. Ran for 5 hours driving in 92 degree heat. Never shut down. It's the first time I've been able to keep it running in 90+ heat.

[TripodRV]

My Onan 4000 was cutting off after a minute of running. Found out it was too full of oil from the factory. I have not changed my oil yet , I have 7 hours and book says do it at 20 hours so I'm still waiting to get more hours on mine before changing. I found some YouTube videos where lots of people were reporting that they think the dipstick FULL mark is wrong. Suck some oil out using a clean windex spray bottle pumper and get it so its about 1/4 above the ADD line. I did this and my generator runs for hours without cutting off. I think oil too high or too low can cause it to do a 36 code (shut down).

[4star]

I tried all that. Mine wasn't getting fuel to the bowl. Too much oil won't do that.

[Johnynorthland]

Originally Posted by TripodRV

My Onan 4000 was cutting off after a minute of running. Found out it was too full of oil from the factory. I have not changed my oil yet , I have 7 hours and book says do it at 20 hours so I'm still waiting to get more hours on mine before changing. I found some YouTube videos where lots of people were reporting that they think the dipstick FULL mark is wrong. Suck some oil out using a clean windex spray bottle pumper and get it so its about 1/4 above the ADD line. I did this and my generator runs for hours without cutting off. I think oil too high or too low can cause it to do a 36 code (shut down).

Our first RV’s Onan generators oil was too low from the factory and use to cut out! So not only did the factory , (not a Jayco), not do their job but the dealer should have done a pre-check also!