| Pressure testing a Walbro carburetor is an
excellent way to determine if there is a possible leak in the inlet needle and seat area.
Walbro diaphragm carburetors have a pop off pressure range between 10 – 16 psi. The
range is due to variations in the metering spring, inlet needle, and seat combination. The
reseat pressure should be no lower than 5 psi. The easiest way to pressure test a Walbro
carburetor is while the carburetor is still on the engine. Simply remove the fuel supply
line and attach the Walbro pressure tester onto the carburetor inlet fitting.
Walbro’s pressure tester part numbers are - 57-11 (0 - 60 psi) and 57-21 (0 – 15
psi) for float feed carburetors. ADDITIONAL INFORMATION: http://www.geistware.com/rcmodeling/glowpower/meter_pin_pressure.htm
Symptoms of a diaphragm carb having a float valve leak: (1) Rough idle, and engine loading up. (2) Fuel dripping from the carb when its not running (3) Lowend needle does not tune well. SOLUTION: Replace the float valve and adjust the lever to its flush position OR use a "W" gauge to set it.
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