;
Step 1: Hook the gauge to the inlet fitting on the carburetor, and
pump it to no more than 10 PSI. The gauge reading should hold steady. If not, immerse
the carburetor in water and identify where it is leaking. If bubbles come out of the
venturi, the inlet needle is leaking. If the bubbles come out around the fuel pump
side or primer flange then the cause of the leak is most likely loose screws or
damaged gaskets. The pressure gauge must hold steady at 10 PSI before
performing step 2.
;
Step 2: While the carburetor is still under pressure from step 1, pump the primer
bulb and the needle on the gauge should drop. Continue until the gauge reading
indicates a slight vacuum. This will pull a vacuum on the metering chamber. The
gauge reading should indicate a vacuum and hold steady for at least one full
second.
;
Step 3: If the carburetor passes step 2, switch the tester to the return fitting on the
flange and pump the bulb. The needle on the gauge should climb and hold each
time. This verifies that the outlet check valve in the
purge primer
flange is working
properly.
Quick test for accelerator pump o-ring.
;
If the carburetor fails step 2, it could be a leaking check valve or the o-ring, or both.
;
Before taking the carburetor apart, a quick check can be made by filling the
accelerator pump bore with some soapy water and pump the
purge primer
bulb. If
the liquid is drawn in, the o-ring is leaking.
