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  1. #1
    Join Date
    Jul 2011
    Location
    St. Paul, MN
    Posts
    61

    Default Carburetor help!

    Got the boat on the hose to do the spring checklist and ran into a few problems...
    I overhauled my Holley 4160 carb last fall and had the boat out a few times after. I went through the carb because the engine would die after bringing to idle speed from cruise and then would not want to start after. I noticed while on the driveway yesterday that when I would shut the boat off, fuel was still being dumped into the engine for 10-20 seconds after. I know that shouldn't happen and was wondering if this was part of the reason I was having problems last year when bringing the boat to idle after cruising. Is there a float adjustment you can do? Is this likely the reason I have no problem starting the boat cold, but then dies coming down from cruising?

    Also... I am not sure I put the choke assembly back together correctly- it does not close when starting cold and in fact starts easier if I manually engage it.

    Any suggestions will help, I am just getting to know how to adjust things, my first 3 years with the boat I haven't had to do anything related to fuel delivery!
    1986 Saltare
    2004 Excursion 6.0
    2004 BMW X3

  2. #2
    Join Date
    Aug 2010
    Location
    Ma/Nh
    Posts
    126

    Default

    I'm not a carb ninja or anything, but generally if fuel is dumping out of the venturi when it shouldn't be, it's either because the floats are set too high, have sunk, or the float valve is not closing, either because it's worn or damaged, or because some junk got in there and is keeping it from closing completely.

    To adjust the floats, you pull off the fuel bowls and bend the little tab that contacts the valve (it takes VERY small bends to move the float height)

    As far as the choke, do you have the wires on in the right place? I believe if you reverse them, it doesn't work right, but I'm not 100% sure on that.
    __________________
    87 Comp

  3. #3
    Join Date
    Oct 2011
    Location
    Jonesboro IN
    Posts
    391

    Default

    On the holleys the float ajustment is the screw on top of the bowl.

    No need to pull the anything apart.

    If the a float is stuck the fuel will dump out of the bowl vents.
    The power valve will dump out like you are holding it wide open.

    90 bravura 351 1.23/1pmc40 Pefectpass stargazer wake
    You only need two tools wd-40 and duck tape
    If it should move and doesn't wd40
    If it moves and shouldent duck tape

  4. #4
    Join Date
    Jun 2009
    Location
    Seattle, WA
    Posts
    25

    Default

    Not to thread jack, but....

    I have the exact same problem on my 89' sunsport with a holley on the 351. Boat ran great first time out for the first 1 hour or so, but when I came back down to idle speed from cruise, the boat stalled out. I pulled the float bowls off drained the fuel, tried to see if the floats were stuck,put it back together. Idled great, but same thing once brought the throttle back off cruise to idle. It looked like it should be at full throttle with the fuel dumping out in to the carb and flooding it. Can I just replace the power valves? The shop wants about $350 for a rebuild, but I think it has to be a simple cheap part. It was rebuilt 3 years ago and probably only 100 hours put on since. Any advice, I have never pulled a carb apart, but mechanically somewhat inclined.

  5. #5
    Join Date
    Jul 2010
    Location
    N.W. Suburbs Chicago, IL
    Posts
    2,307

    Default

    I will never understand why shops are quoting $350 for a carb rebuild. Hell, for less than that, I can go buy a brand new carb off the shelf that has been zero timed and sit this one on the shelf and rebuild it on my own at my own pace.
    '86 Comp TS6M - Reborn 2016
    Riding a HO Sports CX Ski

  6. #6
    Join Date
    Jun 2009
    Location
    Seattle, WA
    Posts
    25

    Default

    agree.Also a rebuild kit is like $40, so I don't know where the extra $300 plus come from.

    I hate to mess with the whole carb since the engine runs perfect, except for this new little quirk it has. Hoping this problem fixed before the weekend.

  7. #7
    Join Date
    Apr 2005
    Posts
    360

    Default

    The 4160 does not have an external float adjustment. You have to take the float bowl off, turn it upside town and make sure the float lever is at a 90 degree angle. If not, bend it to a 90 degree angle.

  8. #8
    Join Date
    Jun 2009
    Location
    Seattle, WA
    Posts
    25

    Default

    thank you, I'll check it out tomorrow. I'll take some pics to show you, just to see if something doesn't look right.

  9. #9
    Join Date
    Aug 2010
    Location
    Ma/Nh
    Posts
    126

    Default

    i just rebuilt mine as well. From everything I've read, fuel dumping out of the venturis when it shouldn't is a clogged float valve, a float set too high, or a damaged/worn out float valve. I can make mine do that very easily by setting the floats a little too high, and make it stop by setting them just a tiny bit lower.
    __________________
    87 Comp

  10. #10
    Join Date
    Sep 2011
    Location
    Amherst, WI
    Posts
    443

    Default

    Quote Originally Posted by matt k View Post
    i just rebuilt mine as well. From everything I've read, fuel dumping out of the venturis when it shouldn't is a clogged float valve, a float set too high, or a damaged/worn out float valve. I can make mine do that very easily by setting the floats a little too high, and make it stop by setting them just a tiny bit lower.
    Matt,

    How close is your float to being level when turned upside down? I know that is the recommended initial adjustment.
    Kevin



    1993 Supra Sunsport
    5.8 351 HO PCM @ 285hp / PCM (40 A) 1.23:1
    Acme 422 Propeller 4 Blade 12.5 X 15.5 RH 1" Bore .105 cup
    Ballast: (2) 540 lb and (2) 350 lb Straight Line Launch Pad
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