Filling Closed Cooling
Section
5. Continue filling closed cooling section until cool-
ant level is 1 in. (25 mm) below filler neck.
!
CAUTION
Avoid seawater pickup pump impeller damage
and subsequent overheating damage to stern
drive unit. DO NOT operate engine without water
being supplied to seawater pickup pump.
Fresh Water Flow Thru Exhaust
Manifold
NOTICE
!
CAUTION
See “Specifications” for approximate
closed cooling system capacity and cool-
ant recommendation.
Models with belt drive seawater pickup pump
must be in the water when running engine be-
cause garden hose will not supply enough water
to system at higher RPM.
6.
7.
8.
9.
With pressure cap off, start engine and run at fast
idle (1500-1800 RPM). Add coolant solution to
heat exchanger, as required, to maintain coolant
level 1 in. (25 mm) below filler neck.
!
WARNING
Do not remove coolant cap when engine is hot.
Coolant may discharge violently.
After engine has reached normal operating tem-
perature (thermostat is fully open), and coolant
level remains constant, fill heat exchanger to bot-
tom of filler neck.
!
CAUTION
Alcohol or Methanol based antifreeze or plain
water are not recommended for use in fresh wa-
ter section of cooling system at any time.
Observe engine temperature gauge to make
sure that engine operating temperature is nor-
mal. If gauge indicates excessive temperature,
stop engine immediately and examine for cause.
!
CAUTION
Front of engine should be higher than rear to
purge trapped air out of the system during initial
filling. This will minimize the possibility of air be-
ing trapped in the closed cooling section which
can cause engine to overheat.
Install pressure cap on heat exchanger.
10. Remove cap from coolant recovery reservoir and
fill to FULL mark with coolant solution. Reinstall
cap.
1.
Remove coolant cap on heat exchanger.
11.
With engine still running, check hose connection,
fittings and gaskets for leaks. Repeat Step 4.
IMPORTANT: Engine overheating is often due to
air being trapped in closed cooling section.
Purge air by running engine at 2000 RPM for 10
minutes.
a
!
WARNING
Allow engine to cool before removing pressure
cap. Sudden loss of pressure could cause hot
coolant to boil and discharge violently. After en-
gine has cooled, turn cap 1/4 turn to allow any
pressure to escape slowly, then push down and
turn cap all the way off.
71518
a - Hex Head Bleeder
12.
Recheck coolant level after first open-throttle
boat test and add coolant, if necessary.
2.
3.
Open hex bleeder on thermostat.
Fill closed cooling system with coolant mixture
through heat exchanger fill neck until coolant ap-
pears at bleeder valve.
13.
Maintain coolant level in coolant recovery reser-
voir between ADD and FULL marks with engine
at normal operating temperature.
4.
Close bleeder securely.
Index
90-823324--2 796
CLOSED COOLING SYSTEMS - 6B-15
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1993, 1994, 1995, 1996, 1997 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(4 votes, average: 4.5 out of 5)
Marine readers have rated 1993 1997 Mercury-MerCruiser GM V8 454 CID 7.4L and 502 CID 8.2L Marine Engines Service Manual Number 16 4.5 out of 5.0 based on 4 product reviews. Hugely helpful service manual! Perfect. Thank you!
Manuals are all Important for Technician
This book is invaluable if you do your own repairs. Great book.
Could not find a copy until a search brought me here.
Excellent print.
Thank you