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
plug and turning the crankshaft over by hand, to be sure
it rotates freely.
CHECKING STARTER MOTOR DRIVE
When the starter motor is activated, the pinion gear
should rise, engaging the flywheel ring gear, and crank
the engine. This action can be observed by removing
the starter motor. If the starter motor drive does not
react properly, inspect the helix and pinion gear for
freeness of operation. If any sticking occurs, this must
be corrected. Proper operation of the starter is
dependent on the pinion gear freely moving on the helix.
See Fig. 70.
Fig. 70 - Checking Starter Motor Drive
DISASSEMBLY OF STARTER MOTOR DRIVE
Remove drive housing from end head. Fig. 69.
To remove the drive gear assembly for cleaning or
replacement, clamp the drive gear in a vise having brass
jaws, to prevent damage to the gear teeth. The lock nut
may then be removed and the starter drive disassembled
for cleaning or replacement.
The pinion gear should be inspected for damaged teeth.
If a sticking condition exists between the pinion gear and
the helix, the parts may be washed in a solvent such as
Stanisol or Varsol. If the sticking condition is not
corrected by cleaning, the complete drive assembly must
be replaced. Individual parts of the drive assembly are
Gear Drive 12V & 120V
ASSEMBLING STARTER MOTOR DRIVE
Reversing disassembly procedure for assembling. See
Fig. 71. Use care to insure drive spacer and retainer
are correctly positioned in drive housing. Note: Do not
lubricate drive assembly. A dry silicone spray may be
used if necessary.
Fig. 71 - Assembling Starter Motor Drive
CHECKING 12 VOLT DC MOTORS
A performance test of the 12 volt starter motor may be
made in the following manner.
Equipment Needed -
A tachometer capable of reading 10,000 RPM.
A 12 volt battery * 0.3 volts.
An ammeter capable of reading 25 amperes.
Connect the starter motor, battery and ammeter as
shown on the accompanying illustration. Fig. 72.
NOTE: To test starter motor ON ENGINE, refer to Briggs
& Stratton #19236 VOA meter Instruction Manual.
Fig. 72 - Checking 12 Volt Starter Motor