Electrical Systems
7.25
Dynam ic Ignition Ti ming Adjustme nt -- All Dom estic Carbur eted Models
W ARNING
When replacing a CDI box on ANY domestic carbureted model, it is very important to
check timing. A new CDI box may be programmed slightly different than the one being
replaced, causing ignition timing to be advanced or retarded too far.
NOTE: Always verify timing of engine at room temperature only (68° F/20° C).
Verify the ignition position at maximum advance (3000 RPM) when checking the timing.
If engine damage has occurred due to a suspected ignition related problem, check the ignition timing at the speci-
fied operating RPM.
Always dial indicate the timing mark before attempting to adjust the ignition timing. To indicate the marks:
1. Remove timing inspection plug from starter cover.
2. Remove front (Mag) cylinder spark plug and install
dial indicator.
3. Rotate crankshaft by hand while observing dial
indicator. As the piston touches the indicator
plunger, the dial will begin to rotate. Find the exact
point where the pointer stops rotating and reverses
direction. This will be Top Dead Center (TDC).
4. While holding crankshaft with piston at TDC, zero
indicator by rotating bezel until “O” on dial and
pointer align.
5. Rotate crankshaft opposite the direction of rotation
about .200² BTDC (2 pointer revolutions).
6. Rotate the crankshaft in the normal direction of
rotation to specifications outlined on pages 7.1 and
7.2.
7. Using a fast drying white ink, mark the flywheel in
line with the projection in the inspection hole to
make it easier to see with a strobe light.
8. V erify proper piston position by repeating steps 2 - 5.
9. Remove dial indicator and install spark plug.
10. Connect a tachometer according to manufacturers
instructions.
11. Connect a timing light to the front (Mag) cylinder.
Start engine and increase RPM to 3000.
CAUTION:
Never operate engine for more than 15 seconds with-
out cooling water. Severe engine damage may occur
from overheating.
Mag End
Dial Indicator
Mark fly-
wheel
in line with
projection
View
through
timing hole
Timing Light
PN 2870630
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