Onan NHC Series Operator's/Service Manual And Parts Catalog page 232

SPARK PLUG GAP
O.OZS" GASOLINE
O.OIS" GAS FUEL
CAUTION
FIGURE 22. SPARK PLUG GAP
IGNITION COIL
To test primary and secondary windings within the
ignition c o i l proceed as follows:
1. Use Simpson 260 VOM or equivalent.
2. Place black lead on ground ( - ) terminal of c o i l and
red lead to positive ( r ) terminal. Primary resist-
ance should read 4.30 (± 10%) ohms (? 7 0 " F .
3. Change resistance setting on ohmmeter. Place
ohmmeter leads inside of spark plug cable holes
(Figure 23). Secondary resistance should read
14,000 (± 10%) ohms (3 7 0 o F .
4. If any of the above conditions are not met, replace
c o i l . Refer to parts catalog for correct part number.
FIGURE 23. COIL TEST
This engine uses a 12 volt, negative
ground system. Alternator must be con-
nected to battery at all times when engine is running.
Do not reverse battery cables.
BATTERY INSPECTION
Check battery cells with a hydrometer. The specific
gravity reading shouldjbe approximately 1.280 a f 8 0 o F .
If one or more cells are low on water, add distilled
water and recharge.
Keep the battery case clean and dry. An accumulation
of moisture w i l l lead to a more rapid discharge and
battery failure.
Keep the battery terminals clean and tight. After making
connections, coat the terminals with a light application
of petroleum j e l l y or grease to retard corrosion.
S P E C I F I C
G R A V I T Y R E A D I N G
. S H O U L D B E
S 1 . 2 8 0 A T 8 0 r F.
FIGURE 24. SPECIFIC GRAVITY TEST
FLYWHEEL ALTERNATOR
The alternator is a permanent magnet flywheel alterna-
tor with a solid-state voltage regulator-rectifier for
controlling output. If ignition spark is weak or if the
battery discharges inspect the following:
Inspection:
1. Check battery cells to make sure they are f i l l e d to
appropriate level adding distilled water as re-
quired. Check specific gravity in each c e l l .
Specific gravity should be 1.280 at 8 0 ° F ; if not,
recharge battery to bring it up to this level.
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