Carburetor Idle Mixture Adjustment - Polaris 1999 Sportsman 400 Service Manual

90
CIIAI' T ER TII REE
Ca r b ureto r Id le Mixt u re Adjustment
• ..;:::=-- - - - - <l--
Timing
pointer
28
32
30
I. Rem ove the recoil starter assem bly as described
in Chapter Five.
2. Remove the llywhe el as described in Chapter
Five .
3. Loosen the stator pla te mounting screws (Fig-
u re 93 ) and rot ate the stator plate to adjus t igni tion
timing. Turn the stator plate clockwise to retard ig-
nition timing or counterclockwise to advance tim-
ing.
4. Tighten the stator plate retainin g screws .
5. Reinstall the flywheel, starter pulle y a nd reco il
starter asse mbly.
The pilot air screw con trols the air/fuel mixture
at idle spee d. Turn ing the pilot ai r screw clock-
wise redu ces the amo unt of ai r and richens the
mixture.
The pilot air screw is preset
by
the manufacturer.
The following proced ure is to be used onl y after the
carburetor has been disassemb led and cleaned or if
the pilot air sc rew is replaced .
I. The pilot air screw (Figure 94) is located on the
bottom of the carburetor. nearest the eng ine.
2. Tum the pilot air screw in clockwise} until it
sea ts lightly.
NOTE
Do
1I()/
damage the sea l or the tip of
the pilot air sere\\' byforcing
it
into its
seat .
3. Bac k th e pi lot a ir sc re w out the nu mber o f
turns specified in Tnh le 6.
4. Star t the engine and allow it to wa rm up to
normal ope ra ting temper atur e (a bo ut 10 min-
utes).
5. Con nec t an accurate portab le tachometer ca-
pable of rending increments of
± 50 rpm.