Onan code 36 April 26, 2018, 09:11:06 pm While driving home after being parked across my Moms driveway and on shore power for near two months, we took a pit stop to nuke some dinner. The gennie started and got through the microwave cycle and then simply petered out and would not restart. Gas tank above a quarter full. We tried it again at home later still no go. Not ev n a healthy crank. Today I got the manual out and retrieved the code that says engine stopped while running. Duh. Resolution actions suggested start with fill gas tank. (Uh oh it’s full) and then spark plug check. Then try air filter. I tried the latter first since It was easiest barehanded. I heard it whine and suck a little air but it sounded bad so I stopped Questions. Can this be locked up and the cylinder is stuck so if I did take the spark plug out it might relieve pressure?Or is this classic fuel line failure? If so. 🤬 I have a full tank!! Sigh. Lydia
Re: Onan code 36 Reply #1 – April 26, 2018, 09:29:29 pm "Or is this classic fuel line failure? If so. 🤬 I have a full tank!! Sigh. "You may just have answered your own question!When my short rubber pigtail cracked to the point it was allowing air to enter the generator fuel line I not only had it replaced but had my service shop (at their recommendation) replace the entire fuel line to the generator with stainless steel. At least you can drive the gas tank nearly dry before repairs are made. You couldn't do that if it was the fuel pump that failed. So how old is that fuel pump now that I'm thinking about it?
Re: Onan code 36 Reply #2 – April 26, 2018, 10:01:08 pm We have an ‘06. 60k on the odometer. I’m going to give it a better look see Saturday. With all the discussion on this topic I. The past memory serves that there are two rubber sections surrounding a solid one and the rubber is st the gas tank and at the generator. So I could hope that the one by the generator is the only one that’s accessible AND leaking. Thus kicking this can down the road a bit?Anyone know of pictures for this issue?
Re: Onan code 36 Reply #3 – April 26, 2018, 10:14:43 pm Never mind on pics. Found it. On Larry’s Flickr. But it doesn’t deal with the near end side so is it only the tank side that rots?!?
Re: Onan code 36 Reply #4 – April 26, 2018, 10:49:25 pm Quote from: Lydia Drake - April 26, 2018, 10:14:43 pmNever mind on pics. Found it. On Larry’s Flickr. But it doesn’t deal with the near end side so is it only the tank side that rots?!?Oh, everything rots with time.The gas tank evaporative lines, on our LD, were rotted to the point where I could tear them apart bare handed.They disintegrated into a greasy powder.The generator has two sections of rubber line, one located at each end of a nylon hardline.The rubber line rots at both ends and develops cracks. The fuel pump produces vacuum that pulls fuel out of the tank, routing it through the nylon hose and rubber lines to the generator. As the line rots, it develops cracks that increase in size as time passes. Eventually the leakage exceeds the fuel pump's capacity to pull enough fuel to start or keep the generator running.The issue isn't as bad with a full tank.You can try just replacing the one rubber hose that connects to the generator, maybe it's your lucky day.Odds are the hose is rotted at point ends.In the first post, you said "We tried it again at home later still no go. Not even a healthy crank." and then"Questions. Can this be locked up and the cylinder is stuck so if I did take the spark plug out it might relieve pressure?"Does the generator crank at all? if so, at its normal speed? Why do you think the engine is seized?if the engine is 'locked up', removing the spark plug will have no influence.You may have two problems.Larry
Re: Onan code 36 Reply #5 – April 26, 2018, 11:06:21 pm "We have an '06. 60k on the odometer."LydiaSo, 12 years old... mine failed before reaching that age!
Re: Onan code 36 Reply #6 – April 26, 2018, 11:45:48 pm 138359 yahoo post by rich Stated his wouldn’t crank and he ipulled the spark plug and spinner it and off it started. Mine doesn’t even remotely shake as it does when one normally attempts a start. It is almost like there isn’t enough battery juice but the code it threw doesn’t indicate that. And how it quit while running proves that out. So I am a tad confused. But will look at gas line first. Perhaps the generator in that other post is older than mine. But it came as close to a similar symptom case as I came up with in a forum search. Lydia
Re: Onan code 36 Reply #7 – April 27, 2018, 09:04:25 am We have had an INTERMITTENT problem with our generator the last year. It starts and runs fine, but after 45-60 minutes it might stop with code 36. It has about 300 hours on it. This week, I finally decided to check the Onan list of causes: gas, oil, air filter, spark plug and fuel filter. All good, but having a spare fuel filter, I replaced it. [It is truly a PIA to get the new filter threaded] After running it for two days longer than an hour just to see if it would fail, it did not. Is it fixed? Blimey if I know.I would suggest it's worth a try, if your generator runs for a long period indicating the fuel line is OK, but then fails. Find someone with small nimble hands that is good to lay on their back to change the filter.
Re: Onan code 36 Reply #8 – April 27, 2018, 10:06:27 am If while doing the 'prime' function the noise of the pump is muted after a couple seconds, it is pulling gas. If it continues the sharp metallic 'clicking' sound, it is pulling air, and you have a fuel supply problem, probably rotted hoses.Steve
Re: Onan code 36 Reply #9 – April 28, 2018, 07:09:24 pm I had some expectations that our code 36 was the fuel filter. NOT.That exhausts the reasons Onan lists, except for mechanical damage.[It has gas, the spark plug is light brown, it's full of oil, new fuel filter and the air filter is clean. It starts readily. It primes without pulling air. Great diagnostic Steve]It shuts down after running awhile when the air temp is above 80-85.I suppose the next step is to throw money at it. I have never read a post where an Onan tech corrected the problem before replacing many parts.Anyone know it uses it's on fuel pump? Amazon.com: Airtex E11015 Electric Fuel Pump for Onan Generator Set: Automotive Quote from: Steve - April 27, 2018, 10:06:27 amIf while doing the 'prime' function the noise of the pump is muted after a couple seconds, it is pulling gas. If it continues the sharp metallic 'clicking' sound, it is pulling air, and you have a fuel supply problem, probably rotted hoses.Steve As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Onan code 36 Reply #10 – April 28, 2018, 07:36:29 pm I had symtoms similar to yours. I replaced the Onan fuel pump and the problem was solved. I did not mention this sooner because in a earlier post I got the impression the Onan would not turn, which made me think the generator had locked up. I took pictures with my cell phone as I took things apart. The Onan part is not all the expensive and easy to get on eBay. Note. Onan does not color code their wires! With a few exceptions all wires are white. The write up on the procedure is in the companion.The Lazy Daze Companion: Generator
Re: Onan code 36 Reply #11 – May 04, 2018, 07:14:42 pm Using your excellent write-up The Companion on how to replace the fuel pump I will tackle that repair when we get home. I did confirm that it's also air temp related. When the thermometer is above 80, it shuts off after running for 15 to 45 minutes. We had some cool weather a few days ago and it ran for over two hours with a light load, the heat strip.Since Alabama has hot summers I will be able to tell if the fuel pump fixes the problem. Otherwise, I guess I need to send a check to Montclair.I will replace the 2007 rubber fuel line at the same time.
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