General Information - Mercury MerCruiser Product Applications Manual

Cooling System
Lubricant, Sealant, Adhesives
Tube Ref No.
Special Tools
Computer Diagnostic System (CDS)

General Information

Mercury MerCruiser engines have either a seawater cooling system or a closed cooling
system. Seawater cooling systems are sometimes called raw water cooling or standard
cooling, while closed cooling systems are sometimes called fresh water cooling. On
engines with seawater cooling, the engine is cooled entirely by the seawater in which the
boat is being operated. Closed cooling systems use a combination of fresh water
(antifreeze and water) and seawater for cooling. Both types of systems are designed to
keep the engine operating temperature at approximately 71 degrees C (160 degrees F)
for optimum performance, fuel economy and durability. (Refer to cooling system flow
diagrams at end of section.)
To monitor the cooling system, a temperature switch is incorporated into the audio warning
system, which alerts the operator of an abnormal condition if the temperature exceeds
approximately 93 degrees C (200 degrees F). A temperature sender is also employed to
operate a temperature gauge at the dash. On dual helm applications, this sender must be
replaced with a dual station sender to obtain the proper temperature reading at both
stations. Refer to the Instrumentation and Controls section for more information.
The cooling system must receive a sufficient amount of seawater under all operating
conditions to operate properly. The design and installation of the seawater supply system
is the boat manufacturer's responsibility. Cooling system components must be constructed,
sized, and installed in accordance with the following guidelines.
Do not operate engine without water flowing through the seawater pickup pump, damage
to the pump impeller and subsequent overheating damage to the engine or sterndrive
unit may result.
Page 7A-2
Description
Loctite 567 PST Pipe Sealant
9
RTV 587 Ultra Blue Silicone Sealer
116
Hose fitting threads and plastic plug threads 92-809822
Sealing surfaces and screw shaft
Monitors all electrical systems for proper function, diagnostics,
and calibration purposes. For additional information, pricing, or
to order the Computer Diagnostic System contact:
SPX Corporation
28635 Mound Rd.
Warren, MI 48092
or call:
USA - 1-800-345-2233
Canada - 800-345-2233
4520
Europe - 49 6182 959 149
Australia - (03) 9544-6222
CAUTION
!
Where Used
Order through SPX
90-863758060 AUGUST 2006
Part No.
92-809825