Onan MJA Series Service Manual page 45

43
IGNITION SYSTEM
The maximum gap should be
;j
~-I
____--..,.
.020 in. ; check it with a feeler
.....
-
--""(""',,,'-­
gauge.
If
the gap isn't correct,
1'--::;,.,
",--~
.1:"":..":;"..:
vf~:;
loosen the
adjust~ent
screw
. . .
/;iif{O .
_!"--;v
T250BTC
!:-:;:"' : .:;.......
(BEFORE
and move the statlOnary con- " , '
~ "'kJ/
tact. Retighten the screw and "•."
~~.;
CE1%fO
recheck the gap.
,>" .
When adjusting the points,
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'0
check to be sure they are clean ' . ,
and not pitted.
If
necessary, . ;
clean the points with paper or
gauze tape.
If
they are defec­
FIG 3.3. C - FLYWHEEL TI.MING
bve or excessively pitted, re­
MARKS AND THE TIMING POINTER
place them - See Sect 3.3.3.3.
For spark plug inspection see
Sect 3. 3. 5. To check ignition timing, see Sect 3. 3. 3. 2 .
3.3.3.2 Timing. - The engine can be timed either stopped or running at
rated speed. With the engine stopped, timing should be set for ignition
at 50 ATC; with the engine running at rated speed, 25 0 BTC. Always
adjust the breaker point gap before timing the ignition.
A. Timing Procedure, Plant Stopped (gasoline fuel).
1. Remove the breaker points' cover, disconnect the lead to the igni­
tion points and install a continuity test lamp and battery so the lamp
lights when the points are closed. ­
2.
Rotate the flywheel clockwise until the TC mark on the flywheel ap ­
proaches the timing indicator, (Fig 3.3. C) .
3.
Then slowly rotate the flywheel clockwise until the light goes out
.
;-
indicating that the pOints have opened. This is the ignition point .
If
timing is correct, ignition will Occur at 50 A TC .
4.
If
ignition timing isn't correct, align the 50 ATC mark and the tim ­
ing pOinter, then loosen the breaker plate capscrews and rotate the
.
.'
plate so the light goes out. Rotating clockwise advances timing,
counterclockwise retards it.
5. Retighten the plate and check timing, step 3.
If timing isIi't correct,
again adjust the plate. Otherwise reconnect the ignition lead and re ­
place thecQver.
B. Timing Procedure, Plant Running
1. Install an automotive timing light on either of the spark plug leads.