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  1. #1
    Join Date
    Jun 2011
    Posts
    113

    Default Indmar Assault 310 Carb issues

    Just replaced my engine with a new crate motor from GM, got it on the water today and I'm having some carb issues I believe. Anyone here familiar with the Holley 4150?

    I adjusted timing with adapter to 10 degrees BTDC, ran the idle air screws out 2 turns each, and set floats so that the fuel is right at bottom of opening.

    Issue:

    I've got a good idle at 800 rpm, but it's rough with and without load from 1100 up to 3000. Under heavy load I get pinging right around 2800rpm. But then after I wind down from 3000rpm on the water I get a bad surging idle, bouncing from 500 up too 900 for a minute or two.

    I tried tuning the idle air screws in a couple turns and back out a couple turns but they have almost no effect on idle surge and roughness between 1100-3000rpm

    Any thoughts?
    Brandon

    2000 Moomba Outback LS
    2001 American Skier LazAir Edition
    1991 Ski Tastic Inboard

  2. #2
    Join Date
    Jan 2008
    Location
    Pensacola, FL
    Posts
    1,584

    Default

    Here is what I have done in the past: Start engine, let warm. Adjust idle screw up to 1000-1050 rpm. Turn adjust idle air screws. When adjusting, the engine will increase/decrease in rpm sound. While "searching" with the screws, you will hear the motor go from great to sputtering, move them back to the "sweet spot". Once done, set your idle screw back to factory setting, @ 750 rpm or so.
    You may need to reset the float level as the carb changes angles as the boat accels/planes/decels.

    Lastly, I would make a slight adjustment on the timing. Timing may be a reason for the ping, but not the surging.
    1997 MasterCraft 205

    2008 Moomba Outback
    1999 MasterCraft Sportstar OB
    1992 MasterCraft 205
    1999 Malibu Response LX
    1987 Marlin Magnum Skier

  3. #3
    Join Date
    Jun 2011
    Posts
    113

    Default

    Totally stumped now...Got on the power valve trip earlier, the machine shop that rebuilt my carb put a 5.5 in it, instead of the 2.5; couldn't find a replacement 2.5 PV in town, so I bought a Holley PV block off, and now I'm even more rich at idle and primary circuit. Doesn't make much sense, never changed the factory 68 jets...any thoughts?
    Brandon

    2000 Moomba Outback LS
    2001 American Skier LazAir Edition
    1991 Ski Tastic Inboard

  4. #4
    Join Date
    Jun 2011
    Posts
    113

    Default

    Edelbrock 1409 ordered. Holley gets an F
    Brandon

    2000 Moomba Outback LS
    2001 American Skier LazAir Edition
    1991 Ski Tastic Inboard

  5. #5
    Join Date
    Jan 2008
    Location
    Pensacola, FL
    Posts
    1,584

    Default

    Smartest move you could make. I am not a Holley fan, once they start having problems.
    1997 MasterCraft 205

    2008 Moomba Outback
    1999 MasterCraft Sportstar OB
    1992 MasterCraft 205
    1999 Malibu Response LX
    1987 Marlin Magnum Skier

  6. #6
    Join Date
    Nov 2010
    Location
    Katy, TX
    Posts
    5,274

    Default

    go fuel injection...
    David

    2017 Moomba Mojo Max Surf Edition, Full Wetsounds

    SOLD***2008 Mobius LSV, Gravity III , Wake Plate, Z5, Exile SX65c's, Exile XM9s, Exile XI12D, Exile Javelin, Exile 30.2***SOLD

  7. #7
    Join Date
    Jun 2011
    Posts
    113

    Default

    Yeah, that Holley had a leak somewhere and I just couldn't pin it down. Then I torqued it down a little too hard and cracked the base plate, wasn't worth my time or money to replace it and continue troubleshooting. I just want to get on the lake at this point!
    EFI..eh..not worth the money, plus I don't know of any aftermarket company that offers coast guard approved kits.
    Brandon

    2000 Moomba Outback LS
    2001 American Skier LazAir Edition
    1991 Ski Tastic Inboard

  8. #8
    Join Date
    Jun 2011
    Posts
    113

    Default

    Just wanted to post an FYI for future searches, if you replace the Holley with an Edelbrock 1409 you'll need an 8 degree spacer wedge, Summit sells them for about $80. Would have saved me several weeks of frustration trying to tune a rich issue everytime we put it in the water!
    Brandon

    2000 Moomba Outback LS
    2001 American Skier LazAir Edition
    1991 Ski Tastic Inboard

  9. #9
    Join Date
    May 2003
    Location
    south east michigan
    Posts
    250

    Default

    How does it run now with the Edelbrock and the wedge?
    jy

  10. #10
    Join Date
    Jun 2011
    Posts
    113

    Default

    Runs great with the Edelbrock, no better or worse than a properly tuned Holley I'm sure. I just had so many problems with the Holley that I wanted to try something different. And, the Edelbrock is easier to setup, tune, and clean when the time comes.
    Brandon

    2000 Moomba Outback LS
    2001 American Skier LazAir Edition
    1991 Ski Tastic Inboard

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