Inspection Of Cooling Water Pressure - TOHATSU MFS 25D Service Manual

31) Inspection of Cooling Water Passage
Check the water strainer 1 for clogging. Clean if
1.
necessary.
2. Place the outboard motor in the water and start the
engine.
3. Check that cooling water is discharged from cooling water
check port 2. If not, check the water pump and cooling
water passage in the engine.

32) Inspection of Cooling Water Pressure

1. Measure the cooling water pressure with putting a T-fitting
for pilot tube of pressure gauge on the cooling water hose
between the fuel cooler and cooling water check port.
2. Start the engine and check the water pressure at each
engine speed.
Engine
Rotation
min (rpm)
-1
850
1500
3000
5000
6000
Shown water pressure values are reference.
3. Check the water pump and cooling water passages inside
the engine if the water pressure is very low.
4st 25/30 2022
Water Pressure (Reference)
kPa psi kgf/cm
2
15 2.18 0.153
30 4.35 0.306
60 8.7 0.612
70 10.15 0.714
70 10.15 0.714
1 Fuel Cooler
2 Drive Shaft Housing Nipple
3 Water Check Port
3
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