carb guru needed Options

[ruddyboys]

I have dual webber 40 IDF, the carb was leaking through the accelerator pump diaphragm. After replacing it the carb over flows throug the top? I checked the needle valve and it moves freely and is attached to the floats. The floats also move freely. Could it be the floats need to be adjusted, if so how. (IMG:style_emoticons/default/pissoff.gif)

[lapuwali]

If BOTH carbs overflow, it's more likely to be too much fuel pressure (2.5-3.5psi). There are inexpensive adjustable regulators available.

If only one overflows, then it's more likely to be dirt in the needle valve, or a worn needle valve, or a misadjusted float.

I seem to remember you saying you just rebuilt these carbs. Did you replace the needle valves? If you didn't adjust the floats, you certainly should. I can't remember the numbers off the top of my head, but there's one number for "float fully down", and another number for "float just kissing the needle valve". There's a ball on the end of the needle valve and it has to NOT be pressed in when measuring the "kissing" number. It's best to do this by holding the float plate vertical with the float hanging down. Angle it so the tab on the float arm is just barely touching the extended ball on the valve.

A misadjusted float not only causes overflow, but can also throw off the mixture if the fuel level is too high or too low.

Finally, really good fuel filters are critical to keeping carbs working properly. Very small dirt particles will clog the idle jets and cause no end of drivability problems.