Onan issue

[WFretz]

I have an Onan 5500 that has low hours on it.


In florida for the winter I turned it on, and it ran no problem, but on the way home it started to act up.


It will start, but shuts down if you take your finger off the start button!


Any clues about where to look or if someone has had similar issue with an Onan?

[MrMark52]

Similar or same issue posts on the board - the “Search” box above is your friend.

Get the Service Manual for your unit - it may be in the Files section above, or can be easily found for free download with a little diligent web searching.

When the symptoms your describing happened to our old coach/unit - it’s 27 year old circuit boards were past their prime. Bought new ones from either Dinosaur Electronics or another place that I can’t remember the name of right now - replaced the old boards, unit began to purr like a kitten until the carb float started hanging up (plastic float - didn’t like the ethanol in the gas - had to make some shade tree modifications to the float to get it to work properly again).

[craigd853]

Originally Posted by WFretz

I have an Onan 5500 that has low hours on it.


In florida for the winter I turned it on, and it ran no problem, but on the way home it started to act up.


It will start, but shuts down if you take your finger off the start button!


Any clues about where to look or if someone has had similar issue with an Onan?

Hello, first easy thing to check is oil, you were moving and the oil is sloshing around. Secondly if the unit shut down due to an issue your red light on your start button that is on the generator should be blinking with a code. If it is, your owners manual will tell you how to read the codes. Good Luck and let us know what you find. Original boards in these 5500 are a pain in the butt, they shut the generator down for a large variety of reasons. I replaced mine because old board was bad, the only 2 reasons it will shut down now is no oil pressure and the stator not producing voltage. I bought it from Flight Systems, this particular board allows you to trouble shoot all issues rather than trying to figure out whats wrong with your genny using the old board.

[MrMark52]

Originally Posted by MrMark52

Similar or same issue posts on the board - the “Search” box above is your friend.

Get the Service Manual for your unit - it may be in the Files section above, or can be easily found for free download with a little diligent web searching.

When the symptoms your describing happened to our old coach/unit - it’s 27 year old circuit boards were past their prime. Bought new ones from either Dinosaur Electronics or another place that I can’t remember the name of right now - replaced the old boards, unit began to purr like a kitten until the carb float started hanging up (plastic float - didn’t like the ethanol in the gas - had to make some shade tree modifications to the float to get it to work properly again).

Thanks Craig853! Flight Systems!

[donr103]

How old is it? Critters love to eat.. nest and short hoses and wires .. when things go haywire and don't make sense then keep critters in the back of your mind all the time.. you could have a dirty carb.. see my old posts on this.. you most likely have bad fuel line.. see my old posts on this.. you may have a bad f/p.. see my old posts on this..
Good luck and keep us posted

[1972VWbus]

Very likely the voltage regulator. If the generator does not see 120v once it starts as soon as you let off the start switch it will instantly shutdown. The Onan 5500 will either have a stand alone VR or it's integrated into the control board itself.

Get yourself a 'Kill O Watt' meter and plug it into an outlet and have one start the generator while you view the meter in volt mode. No volts and you found the issue.

[Cassy]

My issue was the belt. Yes, Onan 5500 Gold Marquis for a belt.