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Thread: Throttle Shaft tolerance on Marine Carb List 80328-1, 4175 650.

  1. #1

    Default Throttle Shaft tolerance on Marine Carb List 80328-1, 4175 650.

    I assume there are multiple threads on this topic, but I'm apparently not searching the forum properly. I could not find any threads and I have to believe this is a very common question. I'm rebuilding the 4175/650 marine carb. I can tell there's some throttle shaft slop in the secondary shaft. What symptom would this produce?

    I have seen a you YouTube on a Holley Throttle Shaft Bushing Kit and the person made it seem really easy. IS this a job an inexperienced person can complete? I do not have a mic and I know that's the only way to really know if the slop I feel is too much. Any guidance is appreciated.

  2. #2
    Join Date
    Jan 2010
    Brisbane, Australia


    Even new carbs will have "some slop" in the secondary, since they run a Teflon ribbon strip for bushings.
    The shaft can't be too snug, otherwise secondary operation will be affected.
    I've done many rebushing jobs with kits you can buy.
    You only need a drill with a smooth low speed.
    I like to have the primary fairly snug, but ream the secondary for a slightly loose fit.
    Regards, Gary

  3. #3


    Thank you. Primary seems tight. I think I'll reassemble & reinstall.

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