MerCruiser 305 CID (5.0L) Service Manual page 766

SERVICE MANUAL NUMBER 24
3. Add coolant solution to heat exchanger, as required, to maintain coolant level at filler
neck.
4. After engine has reached normal operating temperature thermostat is fully open and
coolant level remains constant, fill heat exchanger until coolant level is into filler neck
and begins to flow into coolant recovery bottle plastic tubing.
5. Remove cap from coolant recovery reservoir and fill to "FULL" mark with coolant solu-
tion.
6. Reinstall cap.
7. Lift recovery bottle and plastic tubing above heat exchanger filler neck. Allow coolant
to flow down through tubing to purge air through filler neck fitting.
8. Install pressure cap on heat exchanger.
9. With engine still running, check hose connections, fittings and gaskets for leaks. Also
observe engine temperature gauge to make sure that engine operating temperature is
normal. If gauge indicates excessive temperature, stop engine immediately and
examine for cause.
Allow engine to cool down before removing pressure cap. Sudden loss of pressure
could cause hot coolant to boil and discharge violently. After engine has cooled,
turn cap 1/4-turn to allow any pressure to escape slowly, then push down and re-
move cap.
10. Recheck coolant level after first boat test and add coolant, if necessary.
11. Maintain coolant level in coolant recovery reservoir between "Add" and "Full" marks with
engine at normal operating temperature.
Coolant section of Closed Cooling System should be kept filled year around with recom-
mended coolant solution. DO NOT drain coolant from fresh water section for storage, as this
will promote rusting of internal surfaces. If engine will be exposed to freezing temperatures,
make sure that coolant section is filled with Extended Life Coolant and water solution, mixed
to manufacturer's recommended proportion, to protect engine to lowest temperature to
which it will be exposed.
Auxiliary Hot Water Heater Installation
IMPORTANT: When connecting a cabin heater or hot water heater, certain require-
ments must be met:
•
Supply hose (from engine to heater) and return hose (from heater to engine)
MUST NOT EXCEED 5/8 in. (16 mm) I.D. (inside diameter).
•
Make heater connections ONLY at locations described in the following instruc-
tions.
•
Check complete system for leaks after heater is connected into cooling sys-
tem.
•
Check for overheating condition (of engine) after heater is connected.
Index
90-861327--1 OCTOBER 1999
WARNING
CLOSED COOLED MODELS
Page 6B-17