Float Valve P/N’s

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  • Mumbles


    Replies: 5764
    Topics: 298
    #2077

    What’s the difference between OMC/BRP float valves 396521 and 396522? They both look the same.

    Try that again. I had the wrong P/N. 😳


    frankr

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 6715
    Topics: 51
    #20640

    Beats me. I went to the Sierra catalog and checked the applications and 396520 (18-7038) fits a whole bunch of motors. 396521 (18-7093) fits a whole ‘nother bunch. I couldn’t make sense out of it.


    chris-p


    Replies: 2456
    Topics: 153
    #20642

    I wonder if the hole diameter differs? Angle of the tip of the needle?

    The 396521 seems to cover the small hp motors as well, while the 396520 seems to start at about 90hp motors. Mainly newer motors as well. Well, for us anyways.

    Of course just speculation. I really have no idea.

    I had hundreds upon hundreds of nos needle/seat sets. I separated them out to 2 buckets, 1 for small hp motors, for large hp motors. I mainly do smaller hp motors, so that bucket is getting low. Im going to try the one for the larger hp motors and see what happens once I run out.


    Mumbles


    Replies: 5764
    Topics: 298
    #20652

    OK, thanks guys. The reason I asked was Marine Engine lists the 396522 for a ’57 Fastwin but the proper 439071 kit contains a 396521 float valve. 😕 I know I’ve installed the 396521 before in classics and they don’t seem to know the difference.


    fleetwin

    US Member - 2 Years
    Replies: 4737
    Topics: 46
    #20689

    Be sure to post pictures if you discover the actual difference(s). Seems like this might be an easy trap to fall into creating a difficult problem to resolve!


    dan-in-tn

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 961
    Topics: 78
    #20813

    It is the hole size in the seat. It has to do with flow. Also application. Think about it. Cross flow V-4, V-6 engines use two barrel carbs with only one needle to feed two cylinders, where as other crabs are single cylinder float bowls. I would have to do the research again now (call BRP) to get the specs, but the cross flows use the biggest hole seats I believe.

    Dan in TN


    pappy

    US Member - 2 Years
    Replies: 616
    Topics: 37
    #20824

    In general the gravity fed needle and seats have the larger I.D. over the pump fed assembly. Dan’s exception is also a valid one.
    For drag racing we always bought the 3HP needle and seat assembly for our V8s and V6s. It was the only one that had a remote chance of keeping up with the flow from (8) .096 high speed jets when the throttle went to "hang on".

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