MTD 134-618-000 Owner's Manual page 18

1
TROUBLE SHOOTING CHART FOR ELECTRIC START MODELS
TROUBLE
Engine will not
crank
LOOK FOR
REMEDY
Battery installed incor- The battery m ust be installed with the negative, identified at the terminal post by (Neg, N or -),
rectly grounded. Th' i positive (Pos, P or +) attaches to the large cable from the solenoid. The small
red wire from :he fuse holder or circuit breaker is also attached to the positive terminal.
Blown fuse or circuit
breaker
Replace fuse with 7'h amp. fuse Vi xV/a" Ig. Circuit breaker will reset itself when it cools off.
Fuses or circuit breakers seldom open or fail without a reason. The problem must be cor¬
rected. ChecI for loose connections in the fuse holder. Replace fuse holder if necessary. A
dead short m ly be in the cranking or charging circuit where the insulation may have rubbed
through and«xposed the bare wire. Replace the wire or repair with electrican's tape if the wire
strands have iot been damaged. Note: Look for a wire pinched between body panels, burned
by the exhaus t pipe or muffler or rubbed against a moving part.
Use a hydron leter to check the condition of the battery. The Specific Gravity (s.g.) should be
1.265 at 80" F (1.215 s.g. minimum needed for cranking engine). The reason for the battery fail¬
ing must be (ietermined. (1) Defective battery. Battery will not accept or hold a full charge. (2)
Short circuit. Check for grounded wire. (3) Charging system not working, either engine alter¬
nator or tricki a charger.
Trickle Chare er. Check with multimeter. Charger 725-0578—input 120 V A.C., no load output
13.5 V D.C., nited load current 1 amp. Charger 725-0507—input 120 V A.C., no load output 17.4
V D.C., rated I oad current 1/2 amp.
Alternator (d iai or single circuit) The charging system is an alternator located under the
flywheel. It is unregulated and rated 3 amp. at 3600 r.p.m. A diode (rectifier) is located in the
output lead ji st before the wire harness plug on the engine side.
Diode
Shrink
Tube
To Altei nator
Oil
3 AMP DC
(Batt.)
7 AMP AC
(Lamps)
Black
Wire
Polarized
Plug
Mechanical failure.
(Wires and switches)
The diode chi inges A.C. to D.C. to charge the battery. A bad diode can either fail to charge the
battery or discharge the battery if the alternator is shorted as well as the diode. To test: (1)
Disconnect c larger lead from the battery (small red wire). (2) Connect 12 V small test lamp be¬
tween the 3 emp. D.C. charge lead and the positive terminal of the battery. (3) With the engine
off, the lamp should not light. If it does, the diode and possibly the alternator should be re¬
placed. (4) Sturt the engine. The lamp should light. If it does not,the alternator (stator) or lead
wire is bad an 1 should be replaced.
The interlock system includes two mechanical activatec) switches which are wired in series in
the circuit ussd to energize the starter solenoid. While testing the interlock system, you will
make the mo ver temporarily unsafe by permitting the engine to be started with the blade and
clutch engage sd. WARNING: While testing, disengage the clutch, shut off the blade control, set
the parking b ake and place the gear shift lever in neutral. Attach a wire (minimum 18 gauge) to
the positive erminal of the battery and touch the other end to the small terminal on the
solenoid. If tl le engine does not crank: (1) There is a loose connection or poor ground. (2) The
solenoid may be bad. The solenoid can be checked by using a heavy wire (#8 gauge minimum)
and jumping jetween the two large terminals. If the engine cranks, the solenoid is bad. (3) If
the engine dues not crank when you jump the solenoid, have the starter motor tested by an
authorized ei gine dealer. If the engine does crank, the problem is with one of the safety
switches, ign tion switch or the wire between the fuse holder (or circuit breaker) and the small
terminal on tie solenoid. Note: Look for a poor connection at the switches or a defective
switch. Repla le if necessary.
Engine cranks
but will not
start
Throttle or choke not in
starting position
Check owner s guide for correct position for throttle control and choke (if separate control) for
starting.