Products Description
A bench test quickly checks the pump's basic function off the engine. Here's a simple, direct guide.
1. The Manual Pressure Test (The Core Test)
Connect one hose to the pump's INLET and place it in your fuel container.
Connect the other hose to the OUTLET.
By hand, vigorously operate the pump's manual priming lever (if equipped) or carefully push and pull the central drive arm/lever.
GOOD: You should feel strong resistance on the push stroke and see a strong, pulsing stream of fuel from the outlet hose. It should not suck air back in.
BAD: Little to no fuel output, weak stream, or no resistance indicates worn internal valves, a torn diaphragm, or a severely worn lever.
2. The Leak & Seal Check
Block the outlet hose with your finger (or use the air source to apply very gentle pressure to the inlet).
GOOD: The system holds pressure. Fuel does not leak from the outlet, inlet, or, crucially, from the center shaft seal or gasket surfaces.
BAD: Any external leakage, especially from the center shaft or gasket, means the pump seals have failed and must be replaced.
3. The Drive Arm Inspection
Visually inspect the drive arm that contacts the engine's camshaft.
GOOD: The arm is smooth with minimal, even wear.
BAD: Severe grooving, pitting, or excessive wear means the pump will not provide full stroke and will fail soon, even if it currently pumps.
Conclusion: If the pump passes Step 1 (strong output) and Step 2 (no leaks), it is likely GOOD for basic function. If it fails either, it is BAD and needs rebuilding or replacement. This test checks core mechanical health but cannot verify full pressure/volume under actual engine RPM.