Lubricants; Engine Oil - Arctic Cat Cougar Service Manual

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tured with one sharp edge and one rounded edge.
When installing stamped snap rings in a thrust
situation, the sharp edge must face away from the
part producing the thrust unless the text directs
otherwise. When installing snap rings, observe
the following:
a. Snap rings should be removed and installed
with snap ring pliers. See
Snap Ring Pliers
in this chapter.
b. Compress or expand snap rings only
enough to install them.
c. After the snap ring is installed, make sure it
is completely seated in its groove.
LUBRICANTS
Periodic lubrication assures long life for any
type of equipment. The type of lubricant used is
just as important as the lubrication service itself.
The following paragraphs describe the types of
lubricants most often used on snowmobiles. Be
sure to follow the manufacturer's recommenda-
tions for lubricant types.
Generally, all liquid lubricants are called oil.
They may be mineral-based (including petro-
leum bases), natural-based (vegetable and ani-
mal bases), synthetic-based or emulsions
(mixtures). Grease is an oil to which a thickening
base has been added so that the end product is
semi-solid. Grease is often classified by the type
of thickener added. Lithium soap is a commonly
used thickener.
Engine Oil
Two-Stroke Engine Oil
Lubrication for a two-stroke engine is pro-
vided either by oil mixed with the incoming
fuel-air mixture or by oil injected into the fuel-air
mixture. The models included in this manual are
equipped with an oil-injection system. Some of
the oil settles out in the crankcase, lubricating the
crankshaft and lower end of the connecting rods.
CHAPTER ONE
The rest of the oil enters the combustion chamber
to lubricate the piston rings and cylinder walls.
This oil is burned during the combustion process,
then expelled with the engine's exhaust.
Engine oil must have several special qualities
to work well in a two-stroke snowmobile engine.
The oil must function properly in the high oper-
ating temperature associated with two-stroke en-
gines, as well as flow freely in cold temperatures.
The oil must lubricate the engine sufficiently and
bum easily during combustion. The oil cannot
leave behind excessive deposits. Refer to Engine
Lubrication in Chapter Three.
NOTE
The injection oil used by Arctic Cat
snowmobile engines must also be able to
flow at temperatures of -40° C (-40° F).
See Chapter Three under Lubrication
for additional information.
Four-Stroke Engine Oil
CAUTION
Four-stroke oils are only discussed to
provide a comparison. The engines used
in these models of Arctic Cat snowmo-
biles are two-stroke engines and only
two-stroke oil should be used.
Four-stroke (cycle) oil for ATV, motorcycle
and automotive engines is graded by the Ameri-
can Petroleum Institute (API) and the Society of
Automotive Engineers (SAE) in several catego-
ries. Oil containers display these ratings on the
top or on the label.
API oil grade is indicated by letters; oils for
gasoline engines are identified by an S, such as
SE, SF, SG or SH.
Viscosity is an indication ofthe oil's thickness
or ability to flow at a specific temperature. The
SAE uses numbers to indicate viscosity; thin oils
have low numbers while thick oils have high
numbers. A W after the number indicates that the
viscosity testing was done at a low temperature