25
YM-150A
2. Loosen the two knobs securing the
air filter to the inside of the housing;
then remove the filter.
YM-151A
3. Install the filter and secure using the
two knobs.
4. Install the air filter housing cover
and secure with the clips.
5. Install the left-side access panel.
Spark Plugs
NOTE: Always use the recom-
mended spark plugs in the engine.
See the appropriate specifications
sheet for correct spark plug gap.
1. Disconnect the main harness from the
ignition coils; then remove the ignition
coils from the cylinder head cover.
2. Remove the three spark plugs.
NOTE: Prior to installing the
spark plugs, check the gap
between the electrode and ground
strap. The clearance should be 0.7-
0.8 mm (0.028-0.031 in.).
3. Install new spark plugs. Tighten to
1.3 kg-m (9.4 ft-lb).
4. Install the ignition coils onto the cyl-
inder head cover making sure they
are fully seated. Connect the main
harness to the ignition coils.
5. Install the hood and access panels.
Checking/Adjusting Valve
Clearance
After 40,000 km (25,000 miles), valve
clearance should be checked and adjusted
as necessary.
NOTE: Take the snowmobile to
an authorized Yamaha Snowmobile
dealer for inspection and service.
This service is at the discretion and
expense of the snowmobile owner.
Battery
These sealed batteries after being in ser-
vice require regular cleaning and charg-
ing in order to deliver peak performance
and maximum service life. The following
procedure is recommended for cleaning
and maintaining sealed batteries. Always
read and follow instructions provided
with battery chargers and battery prod-
ucts.
NOTE: Battery maintenance may
be done by the snowmobile owner
if qualified to do so. If the owner
does not feel qualified, take the
snowmobile to an authorized
Yamaha Snowmobile dealer for this
service. This service is at the dis-
cretion and expense of the snow-
mobile owner.
CAUTION
If adjusting spark plug gap is nec-
essary, do not use the center elec-
trode as a leverage point. Damage
to the plug may occur.
CAUTION
It is critical that the checking/
adjusting valve clearance be done
at the recommended intervals or
severe engine damage may occur.
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