??? 9.5 drain valve body

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  • crosbyman

    Canada Member - 2 Years
    Replies: 3587
    Topics: 326
    #6292

    1966 9.5….. what is the "drain valve and body" assembly for on the 9.5 ? ( the one on the extreme lower part of the carb )

    it is early… I am obviously missing something here

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    frankr

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 6715
    Topics: 51
    #52580

    I believe you meant to say on the bottom of the intake manifold. Those are the crankcase puddle drains.


    crosbyman

    Canada Member - 2 Years
    Replies: 3587
    Topics: 326
    #52581

    sounds ok

    thanks for quick reply there is a 9.5 in trouble on iboats…

    would faulty crankcase drain valves reduce crankcase vacum needed to pull in enough gas from the carb …
    the fellow needs to run his sportwin on 3/4 choke all the time ??

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    frankr

    US Member - 1 Year (includes $3 online payment fee)
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    #52583

    No the problem is not the drain valves. High speed jet (orifice plug) in the bottom of the carburetor float bowl is the usual culprit when it has to be choked to stay running. As you no doubt know, those jets have to be absolutely clean without a trace of any dirt or varnish in the orifice.


    seakaye12

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 1117
    Topics: 108
    #52584

    If meticuously cleaning the orifice plug isn’t getting it done….then suggest that he remove the welch plug which exposes the idle system jets…..and meticuously clean that area.

    I recently had a 9.5 that was doing exactly that….needed choke to run at idle and was lean-missing all over the place. Was shaking sooooo bad lol….

    I could spray carb cleaner through the needle valve opening and I could see it squirting through the three idle holes in the carb throat. I even poked wires through the three holes in the throat….all three holes seemed open and clear from the throat side.

    Still ran poorly so I popped the welch plug….cleaned everything from that side….and the problem was fixed. 9.5’s seem to be particularly sensitive to a **very** clean carb.


    garry-in-michigan

    Lifetime Member
    Replies: 3583
    Topics: 31
    #52587

    Those idle cavity welsh plugs come with the tune up kit. I wonder why people are so reluctant to use them. . . 🙄


    seakaye12

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 1117
    Topics: 108
    #52588
    quote Garry in Tampa:

    Those idle cavity welsh plugs come with the tune up kit. I wonder why people are so reluctant to use them. . . 🙄

    Well; I am not particularly reluctant to use them; but it has always seemed to me that if I can remove the slow-speed needle and spray carb cleaner through there…..and watch it spray through the three orifices in the carb throat….then that **usually** means that removing the welch plug will reveal a clean cavity. Not always though lol….

    BTW….the very late model 9.5’s came with a plastic "filler" that went in behind the welch plug. Can anyone tell me why that was used? What function did it have and if it is an advantage….can the plug be used in the earlier motors? OMC #312909


    garry-in-michigan

    Lifetime Member
    Replies: 3583
    Topics: 31
    #52591

    My guess – Venturi effect – increase air velocity to reduce pressure, making it more responsive at low speed. I imagine it could help motors stumbling when coming off idle. . . 😕


    frankr

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 6715
    Topics: 51
    #52592

    I assumed (probably wrongly) that it is because the fuel is flowing sideways through that big cavity and could puddle in the bottom of the cavity. With the filler, the cavity is smaller and less room to puddle. On other OMC carbs, the discharge holes are on the bottom of the cavity–self draining, so to speak.

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