Pressure Test: Mechanical
- Disconnect fuel line from carburetor. Connect line to a pressure gauge. Hold gauge about 16" above pump level. Pinch off fuel return line (if equipped).
- Start engine and allow to idle (using gas in carburetor bowl). Observe pressure gauge. Pressure should be about 4-7 psi (.28-.49 kg/cm2 ) for 4 and 6 cylinder engines, and about 6-9 psi (.42-.63 kg/cm2 ) for V8 engines.
- Replace pump if pressure is too high or low, or if pressure varies greatly with the engine speed.