Engine 12 Volt Dc Control Circuit; Drivc Belt Adjustmcnt; Battery Care; Glow Plugs - Universal M3-20A Operator's Manual

DC ELECTRICAL SYSTEM
ENGINE 12 VOLT DC CONTROL CIRCUIT
The engine has a 12 volt DC electrical control circuit that is
shown on the wiring diagrams that follow. Refer to these dia-
grams when troubleshooting or when servicing the DC elec-
trical system on the engine.
DRIVE BELT ADJUSTMENT
A
CAUTION:
Drive belts must be properly tensioned.
Loose drive belts will not provide proper alternator
charging and will eventually damage the alternator.
Drive belts that are too tight will pull the alternator
out of alignment and/or cause the alternator to wear
out prematurely.
Belt tension adjustment is made
by
pivoting the alternator on
its base mounting bolt.
1. Loosen the alternator adjusting strap bolt and the base
mounting bolt
2. Pivot the alternator on the base mounting bolt to the left or
right as required.
3. Tighten the base mounting bolt and the adjusting strap
bolL
4. Operate the engine for about 5 minutes at idle, then shut
down and recheck belt tension.
BElT TENSION
BATTERY CARE
Review the manufacturer's recommendations and then estab-
lish a systematic maintenance schedule for your engine start-
ing batteries and house batteries.
o
Monitor your voltmeter for proper charging during engine
operation.
o
Check the electrolyte level and specific gravity with a
hydrometer.
o
Use only distilled water to bring electrolytes to a proper
lcvel.
o
Make certain that battery cable connections are clean and
tight to the battery posts (and to your engine).
o
Keep your batteries clean and free of corrosion
21
A
WARNING:
Sulfuric acid in lead batteries can
cause severe burns on skin and damage clothing. Wear
protective gear.
A
CAUTION:
When quick charging the battery with an
external charger, be sure to disconnect the battery
cables from the battery so the quick charge doesn't
damage the alternator diodes.
GLOW PLUGS
The glow plug is a small heater installed in each pre-combus-
tion chamber. They run off the engine starting bauery and
become red hot when activated.
The glow plugs are wired through the preheat solenoid.
When preheat is pressed at the control panel this solenoid
should "click" on and the glow plug terminal should begin to
get hal.
Glow plugs can be checked by unscrewing and holding them
against a good ground (engine block) and turning them on.
The tip should glow red hot. You can also usc an ammeter to
test the power drain (8 to 9 amps per plug), or an ohmmeter
to test resistance (I.! to 1.2 ohms).
A
WARNING:
These glow plugs will become very hot
to the touch. Be careful not to burn your fingers when
testing plugs.
Re-install the plugs in the engine and test them again. The
plugs should get very hot (at the terminal end) with 20 to 25
seconds. If the plugs don't heat up quickly, check for a short
circuit.
A
CAUTION:
Do not keep glow plug on for more than
30 seconds.
_GLOW PLUG
TERMINAL
PREHEAT GLOW PLUGS
~~.
CENTRE SHAFT
~
;;;:;' ""' J
SILICON CAP
y/"" - ' " ' ---
TUBE
FROM PREHEAT
SOLENOID