Oil Pump End Play Adjustment - Polaris Trail Blazer Service Manual

Assembly

Oil Pump End Play Adjustment

The oil pump is a positive displacement type pump. Whenever the oil pump, oil pump bushing, or crankcase are
replaced, the end play clearance must be checked. Target clearance is .008-.024" (.2-.6mm) between the oil
pump boss and the bushing in the crankcase. Symptoms of excessive gear end play include: noticeable engine
noise at idle; pump lever arm binds in the 1/2 open position (will release when engine is rotated).
NOTE:Some 250/300 cc ATV engine oil pumps were produced with a plastic oil pump drive gear (PN 3084825). The
plastic drive gear is no longer available and subs to a metal drive gear (PN 3083429). If you are replacing a plastic
drive gear with a metal one, you must also order and install thrust washer (PN 3083428). If you install the metal drive
gear without the thrust washer you will not be able to achieve the proper drive gear end play as outlined below. Refer
to the Illustration on page 3.22
250/300 Models
Refer to Illustration on following page.
1. Lubricate and install pump drive gear thrust
washer, pump drive gear, and bushing into
crankcase. Make sure parts are completely
seated.
2. Measure the distance from the pump bushing to
the crankcase pump mounting surface. Record
this as measurement A. Example: 4.8mm (Refer
to example below)
3. Measure distance from pump shoulder to pump
mounting flange. Record this as measurement B.
(Example: 3.9mm Refer to example below)
4. Subtract measurement
measurement A (Step 2). See example below.
The difference
measurements is the end play the pump bushings
will have without shims.
clearance from measured and add shims equal to
that amount.
EXAMPLE: A (Step 2)
B (Step 3) --
Target clearance
Total thickness of
shims required
Spacer shim part numbers:
PN 3083671 .15 mm/.006"
PN 3083672 .3 mm/.012"
PN 3083673 .6 mm/.024"
Polaris Sales Inc.
B (Step 3) from
between these two
Subtract the target
4.8
3.9
= .9
(.2-.6 mm)
--
= .3--.7mm
A
B
3.21
ENGINE
EC25PF/EC28PF Engine
4/99