Onan NHC User Manual

BREAKER POINTS
The timing is adjusted during initial engine assembly
and is fixed by the point gap adjustment. To maintain
maximum engine efficiency, change the breaker
points every 200 hours of operation.
Replacement and Adjustment
1. Remove spark plugs.
2. Remove breaker box cover. Rotate crankshaft
clockwise (facing flywheel) until points are fully
open.
3. Remove condenser (screw A) and detach
condenser lead and coil lead screw (screw B).
See Figure 8.
4. Remove two Allen screws (C) and lift breaker
assembly from engine.
5. Replace condenser and point assembly with new
parts and reinstall using above procedure in
reverse order of removal.
6. Adjust point gap by rotating crankshaft clockwise
(facing flywheel) by hand until the points are fully
open. Set the point gap (using flat feeler gauge) at
.016 inch (0.41 mm) by adjusting the socket head
screw (D) inward or outward (Figure 8). A .016
inch point gap is equivalent to 20° BTC.
Make sure feeler gauge is clean and free of any grease, oil or
dirt.
FIGURE 8. SETTING POINT GAP
7. R e p l a ce breaker box cover, coil wire, spark plugs,
and spark plug cables.
Continuity Test
As a check for proper ignition timing a continuity test
may be performed:
1. Adjust breaker points.
2. Remove air intake hose or cylinder shroud to
expose timing marks (Figure 9).
VACU FLO ENGINES:
REMOVE AIR SHROUD FROM RIGHT
CYLINDER TO VIEW TIMING MARKS
FIGURE 9. TIMING MARKS
3. Rotate flywheel clockwise until timing mark is
aligned with the mark corresponding to 20° BTC
on top of gearcase cover.
4. Connect an ohmmeter or a continuity test lamp
set across the ignition breaker points. Touch one
test prod to the coil lead terminal (screw B
Figure 8).
5. Touch the other test prod to a good ground on the
engine.
6. Turn crankshaft against rotation (counterclock¬
wise) until the points close. Then slowly turn the
crankshaft with rotation (clockwise).
7. The lamp should go out or continuity lost just as
the points break which is where ignition occurs. If
timing is early (advanced) the point gap is too
large. If timing is late (retarded) the point gap is
too small. Adjust point gap accordingly.
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Onan NHC Specifications

General

Brand	Onan
Model	NHC
Category	Engine
Language	English