Forum Discussion

deprived's avatar
deprived
Explorer
Aug 28, 2015

Replacing Onan 4000/KY Carb

The carb on my Onan 4000 KY got gummed up and I just replaced it. It runs. Everything is fine.

But - wow - it was such a PAIN. That generator is a masterclass in bad design. I thought it was going to be like changing the carb in a lawnmower (which takes ten or fifteen minutes tops), but, nooooooo. The two bolts that hold the carb in are installed by feel and some help from a dental mirror. It's a massive drag.

Incredibly, the carb is installed by being just sort of wedged in while, at the same time, the gaskets must remain perfectly lined up so you can get the bolts in by feel only. I affixed the gaskets to the carb with copper gasket dressing which helped a little.

My question is this: Did I miss something that would have made this any easier? Has anyone else done this before?

Like I said, the job got done but I just can't believe anyone would design something so poorly.

Grrrrr. :M :@

-edited to fix typo
Class C
  • deprived's avatar
    deprived
    Explorer
    Aug 31, 2015
    j-d wrote:
    Catch that with a long screwdriver and pry the blower housing away from the intake manifold.


    I ended up using a monster screwdriver leveraged on the "roof" of the generating housing to push the blower housing out of the way. I think the arrangement you've described would have worked better. What an insane system.

    The shop manual is very vague, especially on how to remove the intake manifold. The outside nut is easy t get to but the one on the inside? I can't begin to guess how I'd get to that one. And yet the manual states:

    "6. Remove the intake manifold mounting nuts and lift off the manifold. "

    Yeah, I'll do just that.
  • j-d's avatar
    j-d
    Explorer II
    Aug 28, 2015
    I received a tip when working on ours. Take a couple screws out of the blower housing. Remove air filter and of course the fuel line and electric to the carb. Then the two long bolts that pass through the whole business. And THEN put the wingnut back on the air filter stud, upside down. Catch that with a long screwdriver and pry the blower housing away from the intake manifold. That provides clearance for the throttle and choke plates, and to work with the gaskets. Our gaskets actually stayed in place.
  • vern_kelly's avatar
    vern_kelly
    Explorer
    Aug 28, 2015
    yep,

    Posted detail on this a few months ago under TECH forum. Had to take it off and on twice before I got it all cleaned out. Good thing my labor is cheep!

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