Fuel Pump; Operation - Polaris 340 LX 2007 Service Manual

FUEL PUMP

Operation

The fuel pump works by using the positive (pressure) and
negative (vacuum) impulses generated by the upward and
downward movements of the pistons to supply each
carburetor with fuel.
When the piston is on the downward stroke, positive
pressure is applied to the fuel pump diaphragm. The
pressure pushes fuel out to the carburetors. A check valve
prevents fuel from being pushed into the fuel tank during
this cycle.
When the piston in on the upward stroke, negative
pressure (vacuum) is applied to the diaphragm. This
draws fuel into the fuel pump from the fuel tank. A check
valve prevents fuel from being drawn out of the
carburetors during this cycle.
To check the fuel pump operation, disconnect one of the
carburetor fuel supply hoses and place into an appropriate
container. A steady flow of fuel should flow from the hose
when the engine is at idle speed.
To inspect the diaphragm, connect a Mity Vac hand
pressure pump to the impulse fitting. Apply 4 - 6 PSI. The
diaphragm should hold the pressure indefinitely.
Replace cracked, bent or broken check valve flaps, and
gaskets when found.
9923396 - 2007-2012 EDGE/Widetrak LX Service Manual
©2011 Polaris Sales Inc.
Fuel System
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