Regal 3300 Owner's Manual page 80

CHAPTER 3
Engine Cooling System
Outboards use raw water for cooling the engine with intakes at the
gearcase. It is important that this system continues to run unobstructed
at all times to avoid hazardous situations and to ensure a safe voyage.
Raw water is drawn up into the outboard vertical driveshaft housing
through pick-up feeds in the gearcase vicinity. Water passes through
a powerhead thermostat which controls how much water circulates
through the powerhead. The cool water absorbs heat produced by the
engine, before being emitted via the coolant exhaust system.
There is an access hole on the port side of the powerhead which shows
a visual stream of water at all times. If no water is visible with the
engine running shut down the engine and investigate the problem. At
times this relief hole can be plugged by debris.
Impeller/ Water Pump
Periodically, the cooling system water pump and impeller should
be inspected for debris, damage or excessive wear due to use, water
chemistry such as mineral and/or silt conditions. Damaged parts will
affect the system's ability to function, and may cause engine overheating
or damage. Contact your Regal dealer for more information and
maintenance schedules of key outboard engine systems.
Thermostat
If the temperature gauge starts yielding abnormal readings, it may
become necessary to look at or replace the powerhead thermostat after
determining whether it is functioning properly. The thermostat reads
the temperature of coolant and determines whether to open or close a
valve to allow warm sea water to pass into the exhaust manifold. The
thermostat may recirculate hot coolant for the purposes of reaching
standard operating temperatures. If standard operating temperatures
have been reached, the thermostat will open a valve and allow hot raw
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