Control System; Adjusting The Ignition Timing - Yamaha 25BMH Service Manual

CHK

CONTROL SYSTEM

ADJ
CONTROL SYSTEM

ADJUSTING THE IGNITION TIMING

CAUTION:
Ignition timing adjustment on the running
engine must be performed in the test tank
with a test propeller installed on the
engine.
Test propeller
90890-01629
WARNING
While checking the engine, do not touch
the rotating part (flywheel), CDI unit, igni-
tion coil, and any other hazardous areas.
1. Check:
• Ignition timing
Out of specification → Adjust.
Ignition timing (at idle)
25B, 30H: ATDC 2° ± 2°
Ignition timing (at full advance)
25B: BTDC 22° ± 2°
30H: BTDC 25° ± 2°
Engine idle speed
1,100 ± 50 r/min
Full throttle operating range
5,350 ± 100 r/min
Checking steps
(1) Install the timing light
plug lead of cylinder #1.
(2) Install the digital tachometer
the spark plug lead of cylinder #1.
(3) Press the position key "C" on the digital
tachometer.
(4) Start the engine and allow it to warm
up for a few minutes.
Timing light ...................................
90890-03141
Digital tachometer ........................
90890-06760
3-4
E
a
onto the spark
b
onto
a
b