Yanmar 4LHA-HTP Operation Manual page 533

Chapter 6 Cooling Water System
7. Kingston Cock (Optional)
7. Kingston Cock (Optional)
7-1 Construction
The Kingston cock, installed on the bottom of the hull,
controls the intake of cooling water into the boat. The
Kingston cock serves to filter the water so that mud, sand,
and other foreign matter in the water does not enter the
water pump.
Numerous holes are drilled in the water side of the
Kingston cock, and a scoop strainer is installed to prevent
the sucking in of vinyl, etc.
Suction pipe
Hull
Kingston cock cover
Screw
7-2 Handling precautions
Caution the user to always close the Kingston cock after
each day of use and to confirm that it is open before
beginning operation.
If the Kingston cock is left open, water will flow in reverse
and the vessel will sink if trouble occurs with the water
pump.
On the other hand, if the engine is operated with the
Kingston cock closed, cooling water will not be able to get
in, resulting in engine and pump trouble.
7-3 Inspection
When the cooling water volume has dropped and the
pump is normal, remove the vessel from the water and
check for clogging of the Kingston cock.
If water leaks from the cock, disassemble the cock and in-
spect if for wear, and repair or replace it.
Cock
Kingston cock cover
Screw
6-16
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