Troubleshooting; Test Equipment; Bearings - Briggs & Stratton 405777 Series 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 slowly by hand, to be sure it
rotates freely.
WARNING: DO NOT ROTATE ENGINE WITH
ELECTRIC STARTER WITH SPARK PLUGS
REMOVED. ARCING AT THE SPARK PLUG
ENDS MAY IGNITE THE GASOLINE VAPOR
EXITING THE SPARK PLUG HOLE.
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,
bearing, weak magnets, etc.
f. Worn brushes or weak brush spring.
g. Wrong oil viscosity for temperature expected.
h. Battery leads too long or wire too small.
i. Battery too small.
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.
Starter Motor Spins But Does Not Crank Engine −
a. Sticking pinion gear due to dirt.
b. Damaged pinion or ring gear.
c. Starter clutch slipping.
d. Battery faulty or damaged.
e. Incorrect rotation due to reversed motor polar-
ity—all motors rotate counterclockwise viewed
from pinion gear.
Starter Motor Spins But Will Not Stop −
a. Defective starter switch.

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 #19357 or #19390.
The meter may be used to read volts, ohms, amperes and
test diodes (rectifiers), Fig. 2.
2
TSM
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 Operators Manual for procedure for checking
fuses. Replacement fuse is available from your Briggs &
Stratton source of supply. Order Part No. 19449.
Fig. 2 − Digital Multimeter
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. 3.
Fig. 3 − DC Shunt − Tool No. 19359
A tachometer is available from your Briggs & Stratton source
of supply. Order as Tool #19200. The tachometer measures
from 800 to 50,000 RPM, Fig. 4.
Fig. 4 − Tachometer
BLACK
POST
RED
POST