Polaris Genesis 2000 User Manual

FUEL SYSTEM/CARBURETION
Fuel Pump Operation
Fuel Pump Operation
The pump supplies fuel to carburetors. On three cylinder models two fuel pumps supply fuel to each of the end
carburetors and commonly to the center cylinder.
When the piston is on the upstroke
crankcase pressure is low, the
diaphragm in the fuel chamber moves
outward toward the chamber cover.
This causes a negative (low) pressure in
the fuel chamber. The check valve on
the fuel supply side of the chamber
opens, allowing fuel to enter. This
vacuum causes the outlet check valve to
close so fuel cannot return from the
carburetor. See III. 1.
When the piston is on its downstroke,
the pressure from the crankcase
becomes positive causing the
diaphragm to move in the opposite
direction, reversing the pressure in the
pump chamber. This causes the inlet
check valve to close and the outlet valve
to open, delivering pressurized fuel to
the carburetor fuel chambers, see III. 2.
1 Piston on upstroke
Negative
(low)
crankcase
pressure
Inlet check
valve open
Diaphragm
—/—
Outlet check
valve closed
Fuel in
Fuel return
to tank
II. 2 Piston on downstroke
Inlet
check Outlet check f"e'r,eturn
Positive
(high) iiiioi uiicorx wwiww* wi iwvsix tan I/1
crankcase valve closed valve open
pressure
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Polaris Genesis 2000 Specifications

General

Brand	Polaris
Model	Genesis 2000
Category	Boat
Language	English