Onan wont start hot

[mr__old_style]

Onan 5500 Gold starts right up when its cold, even after sitting all off season, but once its good and warm it wont start back up until its sat and cooled for probably an hour or more. Any ideas? No codes show up. Just cranks and acts like it not getting fire.

[Gjac]

You can adjust the choke. Also while it is running you can look at it to see if the choke opens when eng is warmed up.

[mr__old_style]

Gjac wrote:
How are you making out with your problem?

Just got back from 2 1/2 week vaca. in Wyoming. So have not had a chance to do any of the checks that have been mentioned. Problem continued thruout vacation, but we were just carefull not to shut it off in morning before coffee pot was empty!:) It will start back up if I go out and manually hold open the choke(?) so I'm thinking maybe the spring is weak and when it gets hot it wont hold it open, (make sense?)
Thanks for all the suggestions

[96Bounder30E]

Gjac wrote:
I would check for spark right after it dies. The winding in the coil can breakdown at high temp and start right up once it cools down.

This is the exact problem I had with my Onan 4KY......from start up it would run about 20-25 minutes then shut off and not restart for about 3-4 hours.........a new pick up coil solved the problem......

[Gjac]

How are you making out with your problem?

[Gjac]

I would check for spark right after it dies. The winding in the coil can breakdown at high temp and start right up once it cools down.

[MEXICOWANDERER]

This is a question regarding a possible diagnostic procedure. It may be a valid question.

If it is indeed the governor. Would not advancing the throttle position temporarily by hand over-ride the control? Of course the generator electrical must be shut off to the rig.

Is this possible? Care must be used to not overspeed the generator, of course. But knowing Onan they probably spent millions carefully crafting another nightmare.

[Kpackpackkelley]

A full model number and spec letter will get you a service manual.

[Jwmoehrle]

I had a similar issue with my fuel pump. As someone else said, when it dies try the prime and see if you can hear it clicking (running). They are a soltenoid pump and lock up when hot. I found this to be a common problem with others when mine had the problem.

[Y-Guy]

Since this isn't specific to Toy Haulers I'm going to move this thread over to the Tech Issues Forum.

Y-Guy

[Shadowman00]

I had the same problem after installing a new carb on my 5500. My problem ended up being a bad fuel pump. The advice I got was to run the gen until it shuts off, then pull the fuel pump off and see if it is pumping when you try to start it, or even hit the prime button to see if you can hear the pump engage.

It's my understanding there is something within the fuel pump that expands when it's hot and it fails to work once, warm. I put a new pump on mine and it's been running great. Very easy install. Good luck.

[offtohavasu]

Could be governor like mentioned above causing the frequency to be off, or could be fuel pump heating up and failing.

[htr1]

I've owned my marquis 5500 since. 06

The governor spring went out on mine cause the same issue .

The cummins cross point serviced with a new governor.

$197 installed so less if you do it your self.

[Sfla2]

not to sure abt how, find a onan guy or somebody fimilar w 1 but NOT CW

[mr__old_style]

Sfla2 wrote:
ck choke assy when it cools the thermal lets the buterfly release

That sounds probable. What and how do I check it?.