Troubleshooting; Test Equipment; Digital Multimeter; Dc Shunt - Briggs & Stratton Twin Cylinder L-Head Repair Manual

TROUBLESHOOTING

NOTE: If a starting problem is encountered, the
engine itself should be thoroughly checked
to eliminate it as the cause of starting
difficulty. It is a good practice to check the
engine for freedom of rotation by removing
the spark plugs and turning the crankshaft
over by hand.
WARNING: DO NOT crank engine with spark-
plug(s) removed! Firing of the spark plug may
ignite gasoline vapor exiting spark plug hole(s).
1. Engine Cranks Slowly –
a. Additional load affecting performance (see
note above).
b. Discharged battery.
c. Faulty electrical connection (battery circuit).
d. Discharged battery (see alternators).
e. Dirty or worn starter motor commutator, bear-
ing, weak magnets, etc.
f. Worn brushes or weak brush spring.
g. Wrong oil viscosity for temperature expected.

TEST EQUIPMENT

The following is a list of equipment recommended to
test and repair starter motors.

Digital Multimeter

The Digital Multimeter is available from your Briggs &
Stratton source of supply. Order as Tool #19390 or
#19464. The meter may be used to read volts, ohms,
amperes and test diodes (rectifiers) when test leads
are inserted in the appropriate receptacle, Fig. 6.
The Digital Multimeter will withstand DC input of 10 –
20 Amps for up to 30 seconds. When checking current
draw of 12 volt starter motors, the DC Shunt, Tool #
19359, is required.
NOTE: The Digital Multimeter is equipped with
two fuses to prevent damage to the meter
in the event that the input limits are
exceeded. If the meter displays a reading
of 0.00 when testing DC output, check
fuses in meter. Refer to FLUKE 23 Opera-
tors Manual for procedure for checking
fuses. Replacement fuse is available from
your Briggs & Stratton source of supply.
Order Part No. 19449.

DC Shunt

Use with Digital Multimeter. The DC Shunt is required
when checking starter motor current draw on 12 volt
starter motors. Order as Tool #19359, Fig. 7.
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h. Battery leads too long or wire too small.
i. Battery too small.
2. Engine Will Not Crank –
a. Faulty safety interlocks.
b. Discharged or defective battery.
c. Faulty electrical connections.
d. Faulty starter motor switch (open circuit).
e. Open circuit in starter motor.
f. Brushes sticking, etc.
g. Faulty solenoid.
3. Starter Motor Spins; But Does Not Crank
Engine –
a. Sticking pinion gear due to dirt.
b. Damaged pinion or ring gear.
c. Battery faulty or damaged.
d. Incorrect rotation due to reversed motor polar-
ity – all motors rotate counterclockwise
viewed from pinion gear.
4. Starter Motor Spins; Will Not Stop –
a. Defective starter switch.
Fig. 6 – Digital Multimeter
Fig. 7 – DC Shunt – Tool No. 19359
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