Fuel System - Arctic Cat Panther 1974 Manual

FUEL SYSTEM
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General
(Fig. 111 -1)
The fuel system utilized in the Arctic Cat Wankel
Panther snowmobile consists of a fuel tank fuel
line, vapor return line, carburetor and an
exte~nally
mounted fuel pump_ The fuel pump is mounted on
the recoil housing and actuated by a cam that
works integrally with the number of mainshaft
revolutions.
The only source of lubrication for the Wankel
engine is the fuel mixture that is used during the
combustion process and for this reason, significant
importance is placed on fuel mixing. The correct
ratio of gasoline to oil is 25: 1. If the fuel mixture
contains too much oil, the spark plug will
eventually foul and the rotor faces will become
excessively carbo ned because of incomplete
combustion.
The fuel tank, Fig. 111-1, is made of 20 gauge cold
rolled steel and has an approximate capacity of
6.25 U.S. gallons. The outside of the fuel tank is
specially cleaned and coated with a gasoline/oil
resistant paint. The tank is equipped with a vented
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fuel level gauge cap, Fig. "1-1, that allows vapor
gasses to be released to the atmosphere and also
aids in allowing fuel to flow to the fuel pump and
carburetor. If a vent hole would not be provided in
the fuel level gauge cap or if the vent hole becomes
obstructed, fuel will not flow to the fuel pump and
carburetor.
(
Fig. 111-1
Carburetor
(rear view)
Fuel Pump
The fuel tank is also equipped with 2 fittings to
accommodate the fuel line (pick-up with filter and
check valve to prevent back flow of fuel when
engine is off) and the vapor return line, Fig. "1-1.
The section of fuel line that extends down to the
bottom of the fuel tank has a screened filter at the
end that filters out impurities in the gasoline,
which would otherwise make their way to the fuel
pump and to the carburetor. As an added precau-
tion, an in-line filter is also placed in the fuel line,
just before the fuel pump. I n addition to the afore.
mentioned filters, there is also a filter in the fuel
pump and in the carburetor to ensure that foreign
matter does not pass into the engine and cause
severe damage.
To transmit fuel from the fuel tank to the carbure-
tor, a fuel pump is mounted on the recoil housing
and works in conjunction with mainshaft revolu-
tions. The primary function of the carburetor is to
meter a precise volume of fuel and at a specific
time, change liquid fuel to a vapor that is mixed
with air, resulting in a volatile gas. This volatile gas
is ignited by the spark plug, resulting in combus-
tion.
The Walbro WRC carburetor is a diaphragm-type
with an externally mounted fuel pump that
operates off mainshaft revolutions. To retard vapor
locking, the carburetor employs a recirculation
system that returns vapor and excess fuel not used
by the carburetor to the fuel tank. The carburetor
intake hose quiets intake air and catches fuel
spit-back from the carburetor, Fig. "1-1.
111-3