Onan MJA Series Service Manual page 57

55 IGNITION SYSTE M
TROUBLE-SHOOTING CHART
4 -
IGNITION SYSTEM (Cont.)
TROUBLE POSSIBLE CAUSE
RE:rv1EDY
Weak or No Spark
I
Defective hi-tension leads.
I
Replace.
on Some Cylinders
- usually indicatedDefective spark plug.
I
Clean or replace.
by engine missing
Oil Fouled Spark
Plugs
I
Worn rings or pistons.
Worn valve stems or
guides.
Weak battery.
Faulty ignition wires.
Faulty distributor points
(MJC).
Weak ignition coil ..
Too cold a plug.
Gas Fouled Plugs
I
Excessive choking.
(dry black fluffy
depOsit)
Too rich a fuel mixture.
Prolonged periods of no
load operation.
Too <'old a spark plug.
Burned Spark
I
Too lean a fuel mixture.
Plugs (dry, shiny,
glossy deposits on Poor engine cooling.
l
insulator Or pOssi ­
bly cracked insu ­
lator.
Check compression,
Sect 3.7.2.
Check clearance,
Sect 3.7 .
See Sect 3.6.2.
Replace.
See Sect 3.3.4.1.
Test and replace
if
necessary.
Replace with hotter
plugs.
See Trouble-Shooting
Chart 3 - Choke Won't
Open.
Adjust carburetor.
Check optional proce ­
dure.
Change to hotter plugs.
Adjust carburetor.
Check cooling system,
See Sect 3.1.2.