SEAWATER COOLED MODELS
SERVICE MANUAL NUMBER 24
Page 6A-10
90-861327--1 OCTOBER 1999
Seawater Pickup Pump
Output Test
If an overheating problem exists, use this test to determine if a sufficient amount of water
is being supplied to cool the engine.
IMPORTANT: The following information should be observed before proceeding with
test:
•
BOAT MUST BE IN THE WATER FOR THIS TEST. This test CANNOT BE per-
formed with a flush-test device and water hose.
•
The ability of this test to detect a problem is greatly dependent upon the accu-
racy with which it is performed. An error in setting the engine rpm, timing the
test or measuring the water output will affect the overall accuracy of the test
and may produce misleading results. To help ensure accurate results, a shop
tachometer with an error of less than 5% should be used. The boat tachometer
definitely should not be used as its accuracy is questionable. A stop watch
should be used to time the duration of the test to help ensure that the accura-
cy is maintained within one second. An 8 U.S. qt. (7.6 L) or larger capacity con-
tainer should be used to measure water output.
•
Due to the manner in which this test is performed, it may not be possible to
detect a marginal condition or a high-speed water pump output problem.
1. Models With Engine Mounted Seawater Pump - remove water hose, which runs be-
tween pump outlet and engine, and replace with another hose of same diameter, but
approximately 3 ft. (1 m) longer. Hose should be of adequate wall thickness to prevent
it from kinking when performing test. Clamp hose at pump outlet only. Do not clamp hose
at engine end.
75533
a
b
a -
Seawater Inlet Hose
b -
Hose To Cooler
Index
