Ignition Troubleshooting - BRP Johnson 4HP Service Manual

IGNITION TROUBLESHOOTING

Perform the following ignition system tests when the engine is hard to start in order to determine if the
cause is in the ignition or another system.
START
Check spark condition.
No or weak sparks
Check if the spark plug is in good condition
(See page 2-9)
OK
Disconnect the engine stop switch lead
wire (Blue/Red).
No or weak sparks
Check the air gap between the CDI and
coil unit core and the flywheel.
[Air gap: 0.5 mm]
OK
Check the ignition coil resistance.
(See page 3-4)
[Secondary: 8.2 – 12.4 kΩ]
OK
Check spark plug cap for any evidence of
high-tension leak.
OK
Check the spark plug cap resistance.
(See page 3-4)
[Cap resistance: 7.5 – 12.5 kΩ]
OK
OK
Check ignition timing
by using timing light.
Sparks
(Refer to
specifications)
Not good
Sparks
Out of Spec.
Out of Spec.
Not good
Out of Spec.
IGNITION AND ELECTRICAL
IGNITION TROUBLESHOOTING
The cause will not be in the ignition
system.
Not good
Replace the spark plug with new
one.
Check and/or replace the engine
stop switch. (See page 3-5)
Adjust the air gap. (See page
3-7)
Replace the spark plug cap.
Replace the
CDI and coil
unit
3-3