Onan NH-RV GenSet 6.5KW

[jagcb750]

update: I called Cummins yesterday and checked on three kits for my carb. a needle valve and seat kit, an idle mixture kit, the main fuel adjust kit a spring etc. I was going to replace all. He stated 2 of three part numbers that I gave him were showing obsolete in the computer. He stated there wasn't a considerable price difference if I was to just buy the whole carberator. So that is what I did.
The carb arrived today. Talk about fast. I will install the new carb this evening and see if I am in Fat City. I will repost with the results as I find out. Wish me luck.....

[Jim Clark]

Originally Posted by bkahler

It sure sounds to me like the fuel pump is over coming the float/needle valve causing the motor to flood from excess fuel. After you shut the pump off the bowl starts emptying and you're running good for a brief period. I'd say replace the float and needle valve and you just might have your problem licked.

Good luck!

Brad

Or the fuel pump has a bad switch; the pump shuts down on a backpressure switch. If the switch has stuck closed it will just keep pumping away. Electric fuel pumps come in different pressure rating someone could of installed the wrong one. You can get a replacement from any good auto parts store, they are on a wall rack and the mounts are universal.

Since you are unplugging the pump I suspect a bad switch on the pump and not the needle valve. Trying blowing in the fuel line feeding the carburetor and see if it lifts the needle valve. Could be either one, you need a fuel pressure gauge on discharge side of the pump to see at what pressure the pumps shuts down. You could also block the line and see if the pump keeps pumping indicating a stuck switch in the pump.

[jagcb750]

@Jim Clark: OMG Jim, I hope that installing the new carb will do it, because I have bought it already. But if I have to buy a new fuel pump and or switch it won't be the end of the world. I will put on the new carb and if it doesn't fix it I will start looking at the fuel pump and or switch. Oh the pump is stock it still has the stock Onan paint on it.

[Jim Clark]

Just as a point the switch is internal to the fuel pump, which is why it is hard to check.

[jagcb750]

Update: Well I put the new carb on and Success!! No more surging. Well, almost. I Tweaked it out as per the manual and it took the load really well. It hunts right at first and then smooths out, but I believe that is what it is supposed to do isn't it? I had both a/c units going and the fridge and everything was good and smooth. but when I turned on all the lights and one little t.v. it started surging. It runs as smooth as can be on 1 a/c. and the fridge. It can handle the second a/c as long as I don't turn all the lights on. I was wondering if I was just putting too much of a load on it with everything on? Anyway, I think it is running well now.

[Jim Clark]

Originally Posted by jagcb750

Update: Well I put the new carb on and Success!! No more surging. Well, almost. I Tweaked it out as per the manual and it took the load really well. It hunts right at first and then smooths out, but I believe that is what it is supposed to do isn't it? I had both a/c units going and the fridge and everything was good and smooth. but when I turned on all the lights and one little t.v. it started surging. It runs as smooth as can be on 1 a/c. and the fridge. It can handle the second a/c as long as I don't turn all the lights on. I was wondering if I was just putting too much of a load on it with everything on? Anyway, I think it is running well now.

Get out the pencil and do a load study buy recording the demand of each item. I would bet someone you know has a clip on amp probe; normally anyone who works ac has one. Borrow or buy one and clip it on the output feed of the generator and record the load as you turn on items and it will tell you if you are getting full output from the genset. If not you many need to tweak the unit some more.