Onan NHC Series Operator's/Service Manual And Parts Catalog page 109

SPARK P L U G GAP
0 . 0 2 5 " GASOLINE
0 . 0 1 8 " GAS FUEL
C A U T I O N
FIGURE 22. SPARK PLUG GAP
IGNITION C O I L
To test primary and secondary windings w i t h i n 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 (+) terminal. Primary resist-
ance should read 4.30 (± 10%) ohms & 7 0 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 § 7 0 0 F .
4. I f any of the above conditions are not met, replace
c o i l . Refer to parts'catalog for correct part number.
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.
B A T T E R Y INSPECTION
Check battery cells with a hydrometer. The specific
gravity reading should be approximately 1.280 at 8 0 0 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
^ 1 . 2 8 0 A T 8 0 ° F.
FIGURE 24. SPECIFIC GRAVITY TEST
FIGURE 23. COIL TEST
F L Y W H E E L A L T E R N A T O R
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 i f 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 o F ; if not,
recharge battery to bring i t up to this level.
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