MAINTENANCE OF THE M88A1 - OD1672 - LESSON 3/TASK 2
with the STE/ICE (simplified test equipment for internal combustion engines)
or a multimeter, the fault isolation functions described in this task
prescribe the use of a multimeter.
For instructions on the use of the
multimeter, refer to paragraph 1-19, Section V, TM 9-2350-256-20.
It is
understood that troubleshooting any portion of the electrical system is a
complex procedure. The troubleshooting procedure provided here will involve
only the performance of those fault isolation functions required for the
detection of a defective starter.
b.
Troubleshooting. Listed below is an example of the correct procedure
unit personnel would follow for troubleshooting, maintenance, and repair of
the M88A1 starting system, specifically: ENGINE FAILS TO CRANK WHEN STARTER
SWITCH IS PRESSED.
Step 1. Perform the battery serviceablilty test. Testing the batteries for
serviceability is determined by checking the specific gravity of the
electrolyte, and the terminal voltage. Batteries are in good condition and
serviceable when all of the following are met: (If any criteria are not met,
the batteries should be recharged and checked again.
If the correct
readings are not obtained after recharging, the batteries should be
replaced.)
(1) Use a specific gravity thermometer to check the specific gravity of
the electrolyte in each battery; the specific gravity readings should be
between 1.250 and 1.300 corrected to 80 F.
In a tropical climate, the
specific battery reading should be between 1.200 and 1.225.
The specific
gravity between individual cells should not vary by more than .040.
To
ensure proper starting under cold climate conditions, the specific gravity
of a battery should be maintained between 1.275 and 1.300 corrected to 80
F.
The freezing point of a battery's electrolyte depends on its specific
gravity.
Care must be taken never to allow the specific gravity to drop
below that value at which electrolyte freezing would occur; this can be done
by keeping the batteries charged, or by increasing the acid concentration in
the electrolyte.
The electrolyte freezing temperature versus specific
gravity reading for the M88A1 recovery vehicle batteries is provided in
Table 1, on the following page.
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