Community Forums

gkurtz · 10-31-2021, 12:24 PM

I have a 2000 Onan 5.5kw marquis generator which surges several times when starting cold. It does even out and runs great after. It there a electric or automatic choke? Any info would be appreciated?

donr103 · 10-31-2021, 01:20 PM

Could be choke.. but there are a few things to try first..
1.. when is last time you cleaned armature slip rings ? They need to be nice and shiny..
2.. try adjusting the main jet... or you might call it altitude adjustment.. when it's colder outside the gen needs more gas.. air is thicker.. so adjust it out..
Those are cheap.. and of course you have done all basic maintenance like filters.. oil.. plugs.. ect..
Report back to us..
Good luck and let us know what you did and maybe better members then me will help you

gkurtz · 10-31-2021, 04:57 PM

Please explained the armature slip rings and how it relates to the cold start?

donr103 · 10-31-2021, 05:37 PM

Slip rings are one of the most over looked maintenance items.. see FLIGHT SYSTEMS GEN REPAIR . On you tube.. your voltage regulator controls eng and they are the cheapest over looked items..
I am not there.. I only can try to give you opinions.. yes there is an electric choke as long as not lp... it maybe the choke relay.. it is found next to carb on mine.. just under it..
So just trying to help.. and they do control eng..
Good luck and let us know what you did and maybe better members then me will help you

CamJam1 · 10-31-2021, 09:35 PM

It could be many things, but after trying new fuel pumps, filters, fuel line and cleaning the old carburetor, a new $60 carburetor fixed my issues:

https://www.irv2.com/forums/f54/knoc...rs-558278.html

Argosy · 11-01-2021, 05:40 AM

I don't know if I'd be concerned. The rotating mass of the generator is probably greater than the rotating mass of the engine. You've got a rich mixture to get it started when it's cold, that's going to give a burst of RPM when the engine fires which the governor will try to dampen. The governor slams the butterfly in the carb closed but the rotor is going to take time to slow. When it does the RPM will be too slow so the governor opens the butterfly all the way and increases speed.

There's not a lot of finesse to simple governors. Watch the carb linkage, it's open or closed until the engine approaches the correct RPM, lots of rotating mass confuses them. As long as it settles down fairly quickly I think it's just the result of a carb and a governor trying to get a bunch of weight turning the correct speed.

twinboat · 11-01-2021, 06:06 AM

For the first 30 to 45 seconds of startup and running, there is no 120 volt draw on the generator end. The ATS takes that long to engage.

Your symptoms leads to a classic choke issue. More likely not enough choke rather then to much.

Country Road · 11-01-2021, 08:31 AM

Quote:

Originally Posted by CamJam1

It could be many things, but after trying new fuel pumps, filters, fuel line and cleaning the old carburetor, a new $60 carburetor fixed my issues:

https://www.irv2.com/forums/f54/knoc...rs-558278.html

I removed a lot of these carburetors and soaked them in cleaner overnight but the easiest fix is like what you said, replace it. Years ago, removal and cleaning was the fix because they weren’t readily available on line. Generally, not the case now.

If you take it somewhere, they’ll replace the carburetor. We no longer have mechanics. We have techs who replace parts.