What makes a marine carburetor marine?

Discussion in 'DIY Marinizing' started by tuantom, Dec 5, 2005.

  1. tuantom
    Joined: Jan 2005
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    tuantom Senior Member

    Other than the float overflow tubes turned into the barrels, what is different about a marine carb?
    I have an Autolite 4100 from a '66 Ford 352 I'd like use in an upgrade from a 2bbl to a 4bbl on my Ford 351 engine. This carb has four copper overflow tubes that stick straight up. If I could sweat extensions turned down onto the existing tubes (no, it hasn't had gas in it for many years), would that marinize the carb? Or is there more to it? The Autolite seems to be a good choice due to it's solid cast body - fewer gaskets to leak - and it's reputation for reliable performance.
    On a side note - The engine, that I'm now exchanging for a marine block, was a bone stock 351W out of a '74 Galaxy. My Dad used all the external marine parts (water pump, starter, alternator, flame arrestor...) off the Interceptor 289 he was replacing. The carb and intake, however were stock Ford. It performed well for almost 30 years, however it grew pretty tired in the last couple. It'll be nice to have fresh power.
    Also- has anyone used Rapido Marine for repowering? I think I'm going to buy a block from him this spring.
    Thanks,
    Tom
     
  2. gonzo
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    gonzo Senior Member

    The other things to look( I'm not recalling that model exactly) is the choke linkage to the fast idle. In auto carbs it is often open, which would negate the flame arrestor. Also some chokes have an air passage and it must be fitted with a screen.
     
  3. tuantom
    Joined: Jan 2005
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    tuantom Senior Member

    The choke linkage on this carb does come up inside the flame arrestor; however the linkage has a tight fitting washer held up against the carb housing with a spring clip. Not sure if this would suffice. It sounds as if the basic design difference is based on preventing any flame at all from escaping in case the carb coughs.
    Would there be any tuning differences such as float level? I once heard the floats were different to prevent gas from spilling under extreme angles. Maybe thats just the J-shaped overflow tubes, though.
    Thanks,
    Tom
     
  4. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    The washer with the spring clip is fine. There are different float levels depending on the application. Marine engines usually work at higher angles than an automotive. I suppose you can try it as it is. If it leans out, raise the float.
     
  5. cyclops
    Joined: Feb 2005
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    cyclops Senior Member

    I have driven cars up and down STEEP mountain roads for miles and never had problems. Boats always run flat compared to a car. Set the float up and drop to specs. and you will have NO problems.
     
  6. woodboat
    Joined: Nov 2003
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    woodboat Senior Member

    In my experience the car carburator runs way too rich. Granted I usually use quadrajunk. The power valve on them pops open and stays thaty way on a cruise as there is little vacuum cruising at 3000 RPM. I always put the lightest power valve spring and often a leaner secondary rod. Again I am not familiar with the process on the autolite byt suspect the same type of mod is necessary.
     

  7. tuantom
    Joined: Jan 2005
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    tuantom Senior Member

    Thanks for the replies. I'm going to keep it to the original specs and go from there. I've been told Holley power valves work in these carbs, so I should have a wide variety to choose from if it does run rich.
    - Tom
     
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