Adjusting Air Screw - BOMBARDIER 1996 Ski-doo MX Z440 Handbook

Section 04 ENGINE PREPARATION

ADJUSTING AIR SCREW

A01C4FS
1. Pilot bypass
2. Pilot outlet
3. Pilot jet
4. Air intake
5. Air screw
o
NOTE: This procedure may be performed for single and dual carburetors. Never adjust
screws more than 1/4 turn at a time.
1. Turn idle stop screw in until screw contacts throttle valve. Then turn idle stop screw in 2
additional turns.
2. Start and warm up engine. Adjust idle stop screw to 500 rpm above normal idle speed. See hv-
speed fuel system.
Turn air screw in or out using l/4-turn increments until engine rpm peaks or reaches its
maximum rpm.
Readjust idle stop screw to return engine to normal idle speed. See pages low speed fue/
system.
5. Repeat Steps 3 and 4 until engine operates at normal idle speed and air screw is peaked.
6. When air screw is adjusted stop engine. Note the setting of air screw and turn it all the way in. If
it takes less than 1 turn, the pilot jet is too small and a larger one must be installed. If it takes
more than 2-1/2 turns to set air screw, the pilot jet is too large and must be replaced by a smaller
one.
04-64
5
4