17
ONS-332
To install the seat, route the front tab on
the seat through the seat-base hold-down
bracket; then install the seat and secure
using the cap screw.
ONS-328
Towing
If the snowmobile is to be towed by
another snowmobile, do not tow using
the loops in the skis. The tow rope should
be attached to the lower A-arms.
Arctic Power Valve
(APV) System
This RPM-controlled servomotor (servo)
actuated system adjusts the size of the
exhaust port to provide peak performance
throughout the RPM range.
The system consists of an exhaust valve
assembly mounted to the exhaust side of
the cylinder and connected by an adjust-
able cable to an electronic servo mounted
beneath the hood.
0747-751
At low RPM, the exhaust valve is held in
the DOWN position by a return spring.
This gives the engine a “low port”
exhaust design calibrated to provide
maximum low RPM power and improve
fuel economy at trail speeds.
At high RPM, the exhaust valve is raised.
This creates a “high port” exhaust design
calibrated to provide maximum perfor-
mance at high RPM.
NOTE: If the servomotor cycles
three times and then shuts down, the
exhaust valve cable is not adjusted
correctly. The exhaust valve may
also be sticking.
NOTE: Take the snowmobile to an
authorized Arctic Cat Snowmobile
dealer for this service. This service
is at the discretion and expense of
the snowmobile owner.
Exhaust-Controlled
Timing (ECT) System
This system automatically adjusts the
ignition timing to provide maximum per-
formance through a variety of operating
conditions. The ECM receives input on
engine RPM (demand) and exhaust pipe
temperature (engine condition) and
adjusts the ignition timing accordingly.
This system is not adjustable and is main-
tenance free.
If a system fault is suspected, use an ohm-
meter to check continuity of the exhaust
pipe temperature sensor located in the
expansion chamber. A reading of either 0
ohm or infinity indicates a failed sensor.
NOTE: A disabled ECT system
WILL NOT cause engine damage;
however, a failed ECT system will
have slower throttle response and
may produce slightly less top-end
performance.
