Onan MJA Series Service Manual page 17

10 TROUBLE -SHOOTING CHAR'T
TROUBLE-SHOOTING CHART 1, THE ENGINE (Cont.)
TROUBLE POSSIBLE CAUSE RE:MEDY
Engine misfires
at heavy load (con
Valve lash too tight.
i.)
Defective ignition sys­
tem.
Adjust lash, Sect 3.7. 1.
See Trouble-Shooting
Chart 4 ..
Engine backfires
Excess oil con­
sumption, light
blue smoky
exhaust
"
Lean fuel mixture.
!---'
Clogged fuel screen.
Adjust carburetor,
Sect 3.2.5.
Clean, Sect 3.2.2.
Poor fueL Change fuel, Sect 3.2.2.
Spark too late. Time ignition ..
Leaking intake valve.
Check compression
See Sect 3.7. 2.
Improper firing order
(JC).
Inspect ignition dis­
tributor system (cor­
rect order 1-2-4-3).
Poor compression.
r-~~
Crankcase oil too light
or diluted.
See Trouble~Shooting
Chart 8 and Sect 3.7.2.
Change to correct oil
Sect 3. 5.l.
If
diluted,
See Trouble-Shooting
Chart 6.
Engine misfiring. See Engine Misfiring,
this chart.
Excess oil in crankcase.
..c.,~
Engine overheating.
Drain to full level.
See Sect 3.
1.
2.
Defective intake valve
stem oil seal.
Replace, Sect 3.7.
~
orn intake valve, guide
or valve stem.
Replace, Sect 3. 7.
Faulty ignition.
-,~
See Trouble-Shooting
Chart 4.
--,~