MerCruiser 13, Service Manual

Page: 244 / 348

4D - 6 - INSTRUMENTATION 90-816462 2-695
! WARNING
The following test involves the use of intense
heat. Failure to follow appropriate procedures or
warnings can cause burns which can result in se-
vere personal injury. While performing the follow-
ing test, observe these general precautions:
•
Wear personal protective clothing such as
rubber gloves, a non-flammable apron, and
eye protection - preferably full face shield or
safety glasses.
•
The appropriate heat source should only be
electric. Heat source should be operated by a
qualified person. Be sure to follow all instruc-
tions of the manufacturer of the heat source.
The heat source should be checked each time
it is used to be sure it is functioning properly.
•
The thermometer used in the test should be a
high-temperature thermometer with a maxi-
mum reading of at least 300
°
F (150
°
C). Under
no circumstances should the operator allow
temperatures to exceed test specifications.
•
Perform test only in a well ventilated area.
•
Use a suitable container, such as metal, to
hold the water. Avoid use of glass containers
unless the operator first confirms for himself/
herself that the glass container is an appropri-
ate high-temperature vessel.
•
Because the components will reach high tem-
peratures DO NOT handle materials or com-
ponents until COMPLETELY cooled.
2. Follow these instructions:
a. With ohmmeter connected as outlined and
using suitable container, thermometer and
heat source, suspend sender with tip in water.
b. Heat water and observe thermometer.
c. As temperature rises ohmmeter readings
must be within the ranges specified for each
temperature (see chart below).
d. Turn heat source off. Allow water and compo-
nents to cool.
NOTE: While water cools you may recheck ohmme-
ter readings.
72769
b
c
d
a
e
a - Suitable Container
b - Thermometer
c - Heat Source
d - Water Temperature Sender
e - Ohmmeter Leads
Water Temperature Ohms Reading
140
°
F (60
°
C) 121-147
194
°
F (90
°
C) 47-55
212
°
F (100
°
C) 36-41
3. Replace sender if ohmmeter readings are other
than as shown for each temperature.
INSTALLATION
1. Apply Loctite Pipe Sealant with Teflon to threads
of temperature sender.
2. Install sender in thermostat housing and tighten
securely.