Mariner Mercury 105/140 JET, Service Manual

Page: 105 / 797

90-824052R3 JUNE 2002 ELECTRICAL - 2C-3
Adjustments
Carburetor Models
TIMING POINTER ADJUSTMENT
WARNING
Engine could start when turning flywheel to
check timing pointer adjustment. Remove all
spark plugs from engine to prevent engine from
starting.
1. Remove all spark plugs and install Dial Indicator
(91-58222A1) into No. 1 cylinder (top cylinder,
starboard bank).
2. Turn flywheel in a clockwise direction until No. 1
piston is at top dead center (TDC). Set dial
indicator at “O” (zero) and tighten indicator set
screw.
3. Turn flywheel counterclockwise until dial
indicator needle is approximately 1/4-turn
beyond .462 in., then turn flywheel clockwise so
that dial indicator reads .462 in. (11.7mm)
exactly.
4. Reposition timing pointer (a) so that timing
pointer is aligned with .462 in. mark on timing
decal. Retighten pointer attaching screws (b).
b
a
b
5. Remove dial indicator from cylinder.
CARBURETOR SYNCHRONIZATION
1.
Loosen 3 carburetor synchronization screws (a)
to allow shutter plates to close completely.
2.
Position throttle lever so that idle stop screw is
against idle stop and move roller arm until roller
lightly touches throttle cam (b). Adjust idle stop
screw (c) on throttle arm to align mark (d) on
throttle cam with center of roller. Without moving
roller from this position, retighten carburetor
synchronization screws.
a
a
a
b
c
d
54388
3.
Verify throttle shutter plates open and close si-
multaneously during throttle lever operation.
Readjust if necessary.