Onan MCCK - ADJUSTMENTS; CHECK BREAKER POINTS; CARBURETOR

ADJUSTMENTS
CHECK BREAKER POINTS
Refer to Figure 18 for correct gap distances. Replace
burned or faulty points. If only slightly burned, dress
smooth with file or fine stone. Do not use emory paper
or emory cloth. Measure gap with thickness gauge; gap
points at .020”.
Ignition breaket points, Fig. 18,must be correctly gap¬
ped. Crank engine to fully open breaker points (1/4
turn after top center). Loosen locking screws and turn
cam to adjust. Tighten breaker points and re-check gap.
Ignition points should break contact just as the 25°timing
mark aligns with the flywheel timing mark. Final timing
is corrected by properly shifting the breaker point box
on its mounting and using a timing light. If specified
timing cannot be obtained by positioning the breaker
box, make sure timing marks on gears are aligned.
Timing procedures are described in the MCCK Service
Manual, No. 927-355.
CARBURETOR
The carburetor (Fig. 19) has a high-speed main fuel
adjustment (needle A) and an idle fuel adjustment (nee¬
dle B). The main adjustment (needle A) affects opera¬
tion under heavy load conditions. Idle adjustment af¬
fects operation under light, or no load. Under normal
circumstances, factory carburetor adjustments should
not be disturbed. If the adjustments have been disturb¬
ed, turn needles off their seats 1 to 1-1/2 turns to per¬
mit starting, then re-adjust them for smooth operation.
Caution: Forcing the needle against its seat will dam¬
age it. The needle does not completely shut off when
turned fully in. _____
Before final adjustment, allow engine to warm up. Make
idle adjustment with no load connected to the generator.
Use a tachometer, or connect a frequency meter to gen¬
erator output to observe speed or frequency. Slowly
turn idle adjustment out until engine speed (or genera¬
tor frequency) drops slightly below normal. Then turn
needle in until speed (or frequency) returns to normal.
To set main fuel adjustment, apply a full electrical load
to the generator. Carefully turn main adjustment screw
in until engine speed (or output frequency) drops slight¬
ly below normal. Then turn needle out until speed (or
frequency) returns to normal. Proper carburetor adjust¬
ment cannot be assured unless the governor is proper¬
ly adjusted.
Set throttle stop screw (located on carburetor throttle
lever) with no load connected while running at rated
speed. Turn the screw to give 1/32" clearance be¬
tween the screw and pin (Fig. 19).
Figure 19. Throttle Stop Screw Adjustment (Spec A)
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