Important Service Notice; Water Pump Cavitation; Electrical System; Wiring Diagrams - Clarke C18H Instruction Manual

3.4.9 IMPORTANT SERVICE NOTICE

Any time an engine experiences a high coolant
temperature alarm condition the primary cause of the
overheat must be determined and the cause corrected
to prevent a recurring overheat event. Additionally,
if an event of a restricted flow, collapsed hose,
insufficient coolant level or failed pressure cap is
experienced, further investigation of the cooling
system is required.
1) The coolant shoud be drained (after de-
energizing the coolant heater
2) Replace the engine thermostat(s)
3) Remove the engine water pump
and inspect the impeller and seal for damage, replace
as necessary. Reassemble and refill coolant
according to the Installation and Operations
Instruction Manual.
4) Run the engine to verify normal operating
temperature.

3.4.9.1 Water Pump Cavitation

Cavitation is a condition that occurs when bubbles
form in the coolant flow in the low pressure areas of
the cooling system and implode as they pass to the
higher pressure areas of the system. This can result in
damage to cooling system components, particularly
the water pump impeller and cylinder liners.
Cavitation in an engine can be caused by:

Improper coolant

Restricted coolant flow caused by collapsed
hose or plugged system

Coolant fill cap is loose or unable to retain
the required pressure

Insufficient fluid level

Failure to de-aerate

Overheat
3.5

ELECTRICAL SYSTEM

3.5.1 Wiring Diagrams (Only with Engine Gauge
Panel)
Drawing No.
(DC Voltage)
C073037 Instrument Panel
C072736 ECM Harness
C18H-all models
C073017
Engine Harness
Drawing No.
(AC Voltage)
C07651 Jacket Water Heater
Description Reference
Document
Description Reference
Document

3.5.2 Checking Drive Belt Tension and Adjustment

All drive belts must be adequately tightened to ensure
that the battery charging alternator is operating
efficiently. Refer to Figure #22.
To adjust Belt Tension:
Check belt tension:
- Give at arrow C must be approx. 0.5" (12.7mm).
To increase tension of the alternator driving belt:
- Loosen nut at D.
- Loosen nut B on adjustment rod.
- Tighten nut A to push the alternator to the right to
tighten the belt. Do NOT overtighten the belt.
- Tighten mounting nut B to lock adjustment
in place.

3.5.3 Engine Overspeed

In the event of an engine overspeed, the ECM signals
the main pump controller and also affects an engine
shutdown. Should an overspeed condition occur,
investigate the cause and make necessary corrections
before placing engine back in service. The engine
will be locked out from restarting and the PV380
display gauge will indicate an overspeed shutdown.
A red indicator LED will be illuminated. To reset the
engine and clear the overspeed fault, press the far-
right key on the PV380 display gauge. Once reset,
the engine will be ready for restart.
OVERSPEED VERIFICATION
Hold the OVERSPEED VERIFICATION switch in
the "up" position. This will provide the main pump
controller with an overspeed signal and engine
shutdown at 30 RPM's below the rated RPM.
42
A
Figure #22