Odd Onan issue

[rcpd34]

I have an Onan 5500 that has always started easily and run fine. Has about 240 hrs. I have a guy doing some inside work today so I showed him how to start it and turn the heat on as it was cold. He called me and said the generator would only run for about 2 mins then stop. Never had this issue before, so I went over and started it, turned on an electric space heater and let it run about 30 mins. Ran fine. Thinking he was nuts, I unplugged the heater, getting ready to shut it down and the generator quit shortly after the load was removed. Gas tank full with good gas treated with Seafoam. Oil level good. Serviced not to long ago. Anyone have any thoughts?

[allcool]

Rasdog wrote:
Allcool,

Thanks for posting the information on adjusting the govenor on the Onan 5500. I was able to take care of the problem today because of your posts.

Thanks again,

Rasdogs

You're very welcome, glad my posts could be helpful to you...

[fly-boy]

Still think it is the carb.
You could pull the carb out and try cleaning/replacing the jets but I would go with a new carb.

[Rasdog]

Allcool,

Thanks for posting the information on adjusting the govenor on the Onan 5500. I was able to take care of the problem today because of your posts.

Thanks again,

Rasdogs

[allcool]

Macman83 wrote:
Thanks Allcool for posting that picture. I don't have a problem with my genset, but I have read about this issue. I was wondering where all those levers and adjustments were. Always good to have a picture.

You're welcome.
Glad the pic could help.

[allcool]

rcpd34 wrote:
It is code 14. I don't have a meter, but a buddy does. I'm hoping to get him out there later this week now that we have better weather.

OK, do you have the Onan shop service manual that explains how to check/set hz...?
If not, shoot me a pm with your email and I'll send you a link or a copy.

[Macman83]

Thanks Allcool for posting that picture. I don't have a problem with my genset, but I have read about this issue. I was wondering where all those levers and adjustments were. Always good to have a picture.

[rcpd34]

It is code 14. I don't have a meter, but a buddy does. I'm hoping to get him out there later this week now that we have better weather.

[allcool]

Bedlam wrote:
The fact that OP's generator runs under load but shuts down when unloaded is a classic case of governor issues. There is an adjustment procedure for the governor - If it does not automatically regulate under different loads than start looking at replacement or sending to service.

I agree.
But, if one is just a little technically minded and owns a $70-100 meter, its a 5-10 minute job to check/set HZ on the ONAN 5500 gen-set. The correct procedure must be used, but its not complicated to do at all.

Although, for this threads Gen-set, the op is not there yet. He needs to do some more troubleshooting still, to determine if incorrect HZ are the problem, before trying to adjust them. I've explained earlier in this thread what he needs to do...


jmo

[Bedlam]

The fact that OP's generator runs under load but shuts down when unloaded is a classic case of governor issues. There is an adjustment procedure for the governor - If it does not automatically regulate under different loads than start looking at replacement or sending to service.

[pigpen1003]

I have a 5.5 onan 4 months old started good at dealer. got to the desert and ran for 3 hours then stopped. The gen is tested b4 release to the customer. BUT I was advised I had bad gas. replaced carb and drained out gas runs fine now, also if you have a fuel station have it drained to if you suspect bad gas. Use 91 octane use seafome run at least once a month for an hour at full load, two air conditions or etc

[offtohavasu]

As already mentioned from broccoli2, refer to this post:

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27459195.cfm

[allcool]

rcpd34 wrote:
Ok; I finally got out there today first nice day off. Dumped 4 cans of Seafoam in and started it. Ran for 10 sec and stopped would not restart. Code was 36; fuel. I saw the factory fuel filter was still there and remembered that Onan recommends it be replaced with a pass through. I had one on on hand from my prior camper so I swapped it out. Cranked it with the supply hose off and I have fuel. Put it back together and started it. Started up and ran for about 30 mins under various loads. Runs perfect. Removed the load entirely and it dies within 30 sec. Checked the code and it's 14 this time; Overfrequency fault. (Engine governor unable to maintain rated freqency. Corrective actio: take to dealer. Any ideas?

Might want to clear fault codes, retest for shut down and verify its fault code 14 and not 36.

If it is code 14 shutting it down, start gen-set, quickly put it under a load, and connect a multimeter(with hz option). Verify voltage, then set meter to hertz and watch what happens. Note what the hz are under load. Note what hz are when you remove the load. Note what the hz are immediately before it shuts down. Watch the meter carefully. Post results here.

jmo

[rcpd34]

Found thhese helpful instructions on the Woodall's site for the exact same issue:

Gently pry the black cap off
turn the main jet in easy till it bottoms out. count the number of turns
remove the main jet but DON"T loose the spring
and clean the crud off the end of it then use the straw on the can of carb cleaner to spray a bunch of cleaner in the hole
now quickly screw the main jet with spring in to hold the carb cleaner in the bowl allow to sit for an hour or so then gently screw the main jet all the way in and then back it out the number of turns you counted earlier now try to start the genset if it doesn't start after a couple of trys then back the main jet out 1/4 turn at a time till it runs smooth under load and no load allow it to run a couple of hours with load then turn the main jet in till it starts to surge then back it out just till it runs smooth. Shut it down and allow to sit overnight then start it you may have to back the main jet out a little till you find the sweet spot where it starts easily and runs good under load.
Run it a couple of times that week under load with seafoam/techron/B12 chemtool which ever one you like then run once twice a month to keep it clean

[mrxlh]

Over frequency, would lean towards the governor setting, not the carb. A bad carb will deliver less fuel, not more.