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I Have fuel coming out of the carb on my outboard when I pump the the ball on the fuel line too much . Is this normal ?

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  • Daniel Campbell Sep 03, 2010

    I told my buddy this before . He seems to think the ball has to be hard before runnining the motor . Pumping too much may be the reason his oil is broken down / very thin and now blows through the blowby and fouls the plugs . You think ?


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The carb has a valve operated by a float inside the float chamber. It works on a balance of pressure in the fuel line and pressure on the float valve caused by the height of fuel in the chamber. The chamber also has an overflow which depending on the design of the carb will dump fuel into the intake manifold or vent it to the outside of the carb. Increasing the pressure on the line (pumping too much) will force fuel past the valve and may cause it to overflow leading to diffyculty in starting.
An incorrect float level adjustment may also lead to fuel leaking past the valve and into the manifold to the combustion chamber and past the piston rings which would dilute the engine oil while the engine is stationary.

Posted on Sep 03, 2010

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Yes, if you pump too many times this will indeed happen. You only need to do this once, or twice, to "Prime" the carburettor.

Posted on Sep 03, 2010

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Take a look at these images, then click on the 'All' tab to get ethanol resistant fuel line.

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