Carb angle help please.

Discussion in 'Inboards' started by sean-nós, Aug 21, 2012.

  1. sean-nós
    Joined: May 2010
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    sean-nós Senior Member

    Hi guys, on my build when the boat level the 2bbl mercarb is at 12 degrees and I sure it will increase when the boat is in the water,should I get an angled spacer to level up the carb or can they handle this angle.
    Thanks.

    [​IMG]
     
  2. CDK
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    CDK retired engineer

  3. sean-nós
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    sean-nós Senior Member

  4. gonzo
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    gonzo Senior Member

    You need to add a wedge. There are commercially available, or you can make your own.
     
  5. Frosty

    Frosty Previous Member

    Geez I wonder how cars drive up hills or even look at the angle motorycles get to when they pull a wheelie.

    How do those old carb cars do hill climbing up 45 degree hills.

    If you look at the carb you will notice the fuel bowl is at the front or back. This is so that the fuel level remains the same under most conditions.

    Fuel is pulled from the main jet into the carb. The main jet is well under the level of fuel. The fuel is pulled into the body due to a depression in the venturi--it has to be pretty empty to starve it.
     
  6. WestVanHan
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    WestVanHan Not a Senior Member

    I know why wedges are supposed to be used and I've used them but I've always wondered what the real point is.

    Even if the carb is perfectly level when floating in a perfectly calm area,with all the bouncing around and waves and angle changes-especially with small power boats-fuel is always going to be sloshing around in there anyways.

    They must help,I assume.
     
  7. sean-nós
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    sean-nós Senior Member

    The carb Im using is a marine carb and not an auto.
    The donor engine came from a ski boat and was at a good angle when it was in the boat with no wedge on the carb, maybe it is standard to run them like this :confused:

    [​IMG]

    [​IMG]
     
  8. Frosty

    Frosty Previous Member

    Why is your TCV valve open to atmosphere -have you disconnected anything?

    The first engine is not the same as the second.
     
  9. CDK
    Joined: Aug 2007
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    CDK retired engineer

    Even in road vehicles the fuel in the bowl is always in motion, yet the average fuel level doesn't change because for every high "tide" there is a low one.
    But with the carb mounted at an angle and the float bowl being on the high side, the level in the main jet will rise and the mixture becomes richer than necessary.
    If the carb is tilted to 20 degrees or more, the main jet overflow will cause fuel to be dumped in the manifold at idle already.
     
  10. Frosty

    Frosty Previous Member

  11. sean-nós
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    sean-nós Senior Member

    Your right Frosty the engine that was in the boat was a auto engine that someone must have swapped for the original, when I striped it down I found this.

    [​IMG]

    So I bought a new marine long block and manifolds but had to use the old intake manifold I also got a block off kit for the egr valve and choke tube that have to be put on I will also be getting a marine distributor before she goes on the water.
     
  12. Frosty

    Frosty Previous Member

    Ive always advised a after market 4 wheel drive manifold such at the Edelbrock.

    Ive experienced very good result from one years ago.

    If that TCV valve is left open the air will leak in when Temp is reached.

    Dont bother with EGR and what does the TCV valve work anyway since the vacuum on the distributor is disconnected ( as should it be for marine use)

    What block is it. Ive forgotten soo much, Dizzy at the back so thats a Ford init?
     
  13. CDK
    Joined: Aug 2007
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    CDK retired engineer

    Believe me Frosty, it happens.
    A certain amount of vacuum in the venturi is required to pull the fuel from the main jet. With a high level the fuel flows over when the throttle valve is still closed. That also happens when the float arm is bent or the float dented.
    I experienced it with a Merc 3.0LX, lots of soot in the water regardless of the idle setting. Installing a new float solved it.
     
  14. Frosty

    Frosty Previous Member

    Your talking of a fault of a bent needle or leaking float -well of coarse it will flood . The poster is concerned about a mere 12 degrees on a perfectly set up carb. Obviously a carb will suffer running probs it it is inverted.

    The link I included found some carbs having trouble at 60 degrees but the Quadrajet as used on Mercs had no problems .

    Re cap 60 DEGREES . Not 12.
     

  15. sean-nós
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    sean-nós Senior Member

    The old block was a GM 305 chevy and the new one is a 5lt mercruiser they must be the same as the gearbox bolted straight on.
    Maybe I will try it without the wedge and if it gives me problems I will add the wedge.
     
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