SkyTrak 6036 Service Manual - Manual (Page 409)

9.57 Model 6036 Legacy
Electrical System
9.10 ENGINE START CIRCUIT
The purpose of the engine start circuit is to energize the
starter solenoid and engage the starter motor to start the
engine. To start the engine, the ignition key switch must
be in the START position, the park brake switch must be
in the ON position and the transmission shift control
switch (travel select lever) must be in the NEUTRAL
(center) position.
When the ignition key switch (Fig. 9-30) is turned to the
START position, and with the transmission in (N)
NEUTRAL, the starting circuit activates the starter relay,
starter solenoid and fuel shut-off solenoid. The fuel shut-
off solenoid opens a valve that supplies fuel to the
injection pump.
9.10.1 Starting Circuit
The starting circuit functions as follows:
1. Current from the battery flows through the positive
(+) battery cable to the starter solenoid.
2. Current then flows to the fuse box, through the main
fuse and to the ignition key switch.
3. When the key switch is turned to the START position
(Fig. 9-30), current flows through contacts in the
ignition switch to the park brake switch.
Figure 9-30 Ignition Key Switch Positions
4. If the park brake is set, current flows through
contacts in the brake switch to the neutral start
circuit.
5. If the transmission select lever is in (N) NEUTRAL,
current flows through the neutral start circuit to
energize the coil of the starter relay. The relay closes
internal contacts that allow current to flow to the
starter solenoid and starter.
6. The starter solenoid engages a gear on the starter
pinion shaft to mesh with the flywheel, and the
starter pinion and gear begin to spin, in turn, rotating
the flywheel, crankshaft and related components
within the engine.
7. When the ignition key switch is initially turned, the
fuel shut-off solenoid opens a valve to supply fuel to
the fuel injection pump. As the starter rotates the
engine components, the fuel injection pump, and
related lines and injectors supply fuel to the
cylinders.
8. When the pistons compress the injected fuel, ignition
occurs, the engine starts and the starter pinion
retracts.
9. As the engine runs, it drives the alternator that
recharges the battery used during the starting cycle.
10. When the ignition key switch is released it returns to
the RUN position where it directs current to the fuse
panel, that in turn distributes electrical current for the
operation of vehicle controls, gauges and other
equipment.
OT0680
OFF RUN
START