Adjusting Idle Speed - Mercury 15XD Service Manual

TIMING/SYNCHRONIZING/ADJUSTING
MECHANICAL SPARK ADVANCE MODELS
20 JET/20/25 1997 AND NEWER
1. Using approved test procedure, place the outboard in "Forward" gear and check the
maximum and idle timing. (If not within specifications, adjustment will be required)
a - Timing Mark
b - Maximum Timing Jam Nut
c - Maximum Timing Screw
d - Idle Timing Jam Nut
e - Idle Timing Screw
ADJUSTING MAXIMUM TIMING
1. Loosen maximum timing jam nut and turn maximum timing adjustment screw in/out
to obtain specified timing.
NOTE: Turning screw out will "advance" timing. Turning screw in will "retard" timing.
ADJUSTING IDLE TIMING
1. Loosen idle timing jam nut and turn idle timing adjustment screw in/out to obtain speci-
fied timing.
NOTE: Turning screw in will "advance" timing. Turning screw out will "retard" timing.
NOTE: Outboards equipped with a thermostat will have a "Sporadic" tell tail water dis-
charge.

Adjusting Idle Speed

1. Start the outboard. After the outboard starts, push the primer knob to the "Full In" posi-
tion, and immediately check for water at the tell tail and idle relief holes. After allowing
the engine to warm up, turn the primer knob to "Full Counterclockwise" position. (Tell
tail pressure should be per General Specification).
2. Run engine at 3500 R.P.M. and check stop button function, and lanyard stop switch
function.
Page 2C-8
MAX
40 3 0
BTDC
IDLE
2 0 1 0 0
a
b c
e
d
54966
90-826883R2 JUNE 1998