Troubleshooting - Yanmar 3YM30 Sevice Manual

9. Cooling water system

9.7.6 Troubleshooting

Refer to the following countermeasures for difficulties that arise.
Problem
1. Pump does not turn
2. Pump turns but does not draw
up water.
3. Pump turns, but the amount of
discharge is low.
4. Water leakage from pump
5. Pump draws up bilge, but motor
stops when hand is removed
from starter switch.
6. Motor does not stop, when
there is no bilge water left
Cause
Faulty wiring
Faulty battery
Faulty starter switch
Faulty pump
Draws up air.
Low voltage in battery.
The distance between the pump
and the surface of the water is too
great.
The pump is too high.
Pump intake is weak.
Clogged strainer
Hose is broken or damaged.
Water leakage from packing
Faulty pump seal
Faulty diaphragm switch
Damaged diaphragm switch
Clogged strainer or hose
Damaged diaphragm switch
175
Countermeasure
Check the wiring between the
motor and battery.
Check to see if the specific gravity
of the battery fluid is greater than
1.25.
Recharge or replace the battery.
Consult your local dealer.
Consult your local dealer.
Check hose connections.
Retighten pump screws.
Check to see if the specific gravity
of the battery fluid is greater than
1.25.
Recharge or replace the battery.
Lower the pump. (Position the
pump so that it is closer to the
surface of the water.)
Lower the pump. (Position the
pump so that it is 50-70 cm above
the bottom of the boat.)
If intake is still faulty after priming,
consult your local dealer.
Clean strainer.
Check for damage and repair. If
incorrect hose has been used,
replace with the regulation type of
hose.
Retighten pump screws.
Consult your local dealer.
Check for loose wiring in
diaphragm switch and correct.
Consult your local dealer.
Clean strainer or hose.
Check for continuity of diaphragm
switch terminal.
Consult your local dealer if there is
continuity.