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BeeeGeee's avatar
BeeeGeee
Explorer
Jan 21, 2021

Onan 4000 Intake Manifold replacement

Hello all, I am the second owner of a 2010 Forest River SandStorm 210SLC with a Onan RV QG 4000 EVAP Spec: K. The previous owner had a lot of carb issues and would replace the carb every year or so. During one of his routine carb changes, it looks like he busted the end of a bolt in the intake manifold leaving only one bolt holding it together. I'm looking to replace the intake manifold but can't find much info on how it comes out. Its very tight and was able to loosen it but its pretty locked in with another parts of the generator. (I'm looking to replace as part of the threads are stripped as well due to his effort to fix)

Has anyone had the pleasure of replacing their intake manifold on their Onan 4000?

Thanks,
Brett
  • Gdetrailer's avatar
    Gdetrailer
    Explorer III
    Jan 21, 2021
    Looks to me that carb adapter was attached BEFORE the metal piece to the left (generator body?).

    If that part to the left is the gen body, then I suspect the gen body WILL have to be separated from the engine before the carb adapter will ever come off the studs..

    If the carb adapter is aluminum, you could have a new "ear" fabricated and welded on if you can find a welding/fab shop that specializes in in aluminum fab and repair..

    If pot metal (zinc) you are out of luck, pot metal doesn't weld..

    Doubt it is cast iron, pretty obsolete now days, welding cast iron is tricky, can be done but temps must be controlled to do it properly..

    If nothing else, fabricate a bracket that you can bolt to the backside of the adapter (where the cast in PN info is)..
  • BeeeGeee's avatar
    BeeeGeee
    Explorer
    Jan 21, 2021


    Here's a pic, you can see I've got the lower bolts loose, but there is a the metal piece keeping the intake manifold from sliding off the studs.

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