onan generator problem


jkill2001

New Member
i have a 5000 watt onan generator with about 700 hours and i've had to bring it to a rv dealer to have it checked at. the problem im having with it is keeping it running. first time the gas was getting into the crank case and running on 1 cylinder. well no more than 2 weeks later i go to crank it and it won't even run now. will run for 3 secs and die. i smelled the oil again and it seems that it has the same problem again. they said they replaced the following parts

check valve
oil of course
oil filter
air filter
2 sparkplugs

anyone ever heard of such a problem and if so what else could it be?
 

Gary B

Senior Member
onan generator problem

Hi jkill2001, sounds to me to be a carb problem, could be the choke is staying on or the float needle and seat not sealing or could be sinking float assy. Thats my best guess from here, hope this helps some.
:) :laugh: :cool: :bleh: ;) :approve:
 

Poppa

Member
onan generator problem

Hmm' The answer is right on target. Bulls eye.

The problem is in the carb, namely with the needle valve and seat.


I don't know how handy you are with tools but a 7/16 or a 1/2 inch wrench and a couple screw drivers will sae you some money if they are charging to service the gen set.

Something to think about is most rv dealers charge upwards of $75 and hour and your local mechanic shop could do the fix.
 

jkill2001

New Member
onan generator problem

well the good thing is that i work at this dealer but im going to have them fix it but im going to tell him im not paying for it since they never actually fixed the problem. i'll let them know about the carb. i hope thats it and not anything majorly wrong with the motor

btw thank u garyb for the quick response as well as u poppa.
 

Poppa

Member
onan generator problem

No problem because it is the carb. Your fuel pump puts out somewhere between 2 and 4 pounds pressure and when you shout the gen down there is still pressure on the fuel system and it bleeds by the needle valve and runs down the intake to the which ever cylinder that has open valves then past the rings to the crankcase.

I know this all too well from some of my racing engines in the past that I had high pressure, high volumne fuel pumps on.
Also had the same problem with a tractor that had a gravity flow fuel tank. Got ready to run it one day and there was no fuel in it. Got an my sons behind about syphonning gas out of it for his car. Had to apologize because after I put gas in it I checked the oil before starting as ususual and man was it way above full and TIN TIN as the fench man would say
 

C Nash

Senior Member
onan generator problem

jkill2001, I vote with the others on the carb. Sit down when they give you the price of a kit for thr onan. You might be able to purchase a new carb cheaper than just a neddle & seat if it is an older Onan.
 

jkill2001

New Member
onan generator problem

well actually i felt kinda stupid today when it ended up just being the carb being set too lean. they manager just adjusted the carb very little and its purring perfectly and holding loads of my 2 a/c units just fine
 

Gary B

Senior Member
onan generator problem

Its good to hear that you got it going jkill2001, sometimes it just a little thing like that :) :laugh:


:) :laugh: :cool: :bleh: ;) :approve:
 

Poppa

Member
onan generator problem

Don't hold your breath and feel toooooo stupid. If you were geyying gas in your oil and was having to change the oil and filter RUNNING LEAN WON'T DO THAT be prepared for the same senario in the future.
 

jkill2001

New Member
onan generator problem

well i think the only reason i was smelling gas was cause i flooded it and since i haven't ran it much from the last problem there might have still been a resedue of gas. but last time the gas had filled the entired crank case and i know that isn't now.
 
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