Checking And Selecting Throttle Valve - BOMBARDIER 1996 Ski-doo MX Z440 Handbook

Section ENGINE PREPARATION
04

CHECKING AND SELECTING THROTTLE VALVE

, A01C2WS
2.0
2.5
3.0
Operate engine at low throttle settings, accelerating from idle to 1/4 throttle.
2 If engine bogs during acceleration, there is probably insufficient fuel. Turn in air screw about 1/
4 turn at a time. If engine acceleration is improved, after adjusting air screw, the throttle valve
cutaway needs to be decreased.
3. If engine runs rough or smokes excessively during acceleration, there is probably too much fuel.
Turn out air screw 1/4 turn at a time. If engine operation is improved, the throttle valve cutaway
needs to be increased.
o
NOTE : Illustration above indicates fuel flow according to throttle valve size and the
amount throttle valve is opened.
4. Increase or decrease throttle valve cutaway size in 0.5 steps.
5. Return air screw to its original setting and operate engine at low throttle settings. Accelerate
engine from idle to 1/4 throttle; engine should accelerate smoothly.
6. As a final check, change the position of the air screw. If this does not significantly affect engine
performance (as in steps 2 and 3), the throttle valve is correct.
04-68
5 15 25 50
Throttle valve opening (%)
75 100