Onan code 36

[TNTP]

I have a 5500 Marquis Gold....my engine dies for no reason after running for long periods of time 30mins-10hrs, like it is running out of gas bogs down few times then dies. This code says replace the plugs, filters(fuel-air) and check for mechanical damage which I did.

I know it's not from vapor lock, removing the cap does nothing. I've been advised it may be fuel line collapsing.

Also says check and fill the gas tank, it's full. Says-(note: The genset fuel pick pick-up tube is probably higher up in the fuel tank than the vehicle engine pick up" huh? What does that mean.

[Tincup]

The generator fuel pick up line in the gas tank doesn't go down to the bottom of the tank. Usually, only to 1/4 of a tank of gas. In other words, don't let your fuel get below 1/4 of a tank or the generator will not only quit, but not start. That's so you don't run out of gas due to running the generator while your in the middle of no where.

By the way, where is no where and how do I find the middle of it?

I had a similar experience with the genny quitting, it turned out to be the wrong grade of oil, it would get hot and fool the oil pressure gauge into thinking there wasn't enough oil.

[TNTP]

You are the MAN! This didn't start happening until I changed the oil and I did use 20W-50 since Walmart did not have 15W-40 I normally use..did cross mine mine but I had no idea they can sense oil viscosity that well....I'll drain it and get a new filter. Says on gen I can use 30wt above 32F I'm in So Cal it nevers gets below that or should I stick with 15W-40 10F-100F? Thanks again!

Been nice if the owners listed that as a possibility under the code and a low oil pressure code come up.

[Gary RVRoamer]

Plain 30 is fine if the temps are always above 32.

Don't know about your 5500, but on my QD 7500 there is a low oil pressure fault code - it is "2".

The generator only senses oil pressure, but viscosity can affect that a bit. 20W50 is a thicker (greater viscosity) oil than 10W40, so it is possible the oiling system cannot get the pressure up quite as high, or that some tiny passages do not get as much oil.

[SuperGewl]

15w 40 Diesel Oil is what the actual Onan oil is. I use AMSOIL 5W 40 Diesel 100% synthetic. It covers the range and besides I have some left over from my Dodge. Generator actuall runs better now.

[FDchief]

I run shell rotella 5w-40 full synthetic. Have had good experience with it.

[GetnBusy]

I had the same issue and I had a small leak in the carb .... Replaced it and it runs like a champ. I doubt the oil viscosity is your issue. Just my $0.02 worth