Fuses - Stiga MPV 320W Workshop Manual

WORKSHOP MANUAL Chapter EDITION PAGE
MPV 320W / 520W 7 - ELECTRICAL SYSTEM 2017 58 /
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If the meter indicates proper voltage across the coil but the device does not function, remove the
power, disconnect the wiring and check the continuity of the coil with an ohmmeter. The meter
should indicate resistance, in the order of 3 to 5 ohms, if the coil is intact. A high resistance indi-
cates an open coil and a faulty device.
There are also a number of mechanical issues that may cause the problem.
The starter solenoid used on STIGA machines is a sealed unit used to actuate the starter motor
on the engines. These solenoids may have three or four connections. The two major connections
carry high current to operate the starter motor. The minor connections are connected to the coil
and carry the control current.
To check the solenoid, disconnect the cables to the starter motor, turn the ignition switch to the
start position, and listen for the solenoid to snap inside contacts closed.
If no snap is heard, check across the coils with a voltmeter. The voltage should read 12 volts with
the ignition switch in the «START» position. If no voltage appears, the defect is in the start circuit.
If the voltage is correct, turn off the power and check continuity of the coil with an ohmmeter. If the
coil is open, the solenoid is faulty and must be replaced. If the coil has the proper voltage applied,
and the continuity check indicates the coil is intact, the solenoid plunger is stuck or the contacts
are welded shut and the solenoid must be replaced.
If the solenoid snaps shut, but the starter motor does not work, check the power contacts with an
ohmmeter. If there is no continuity when the solenoid snaps shut, the contacts are faulty and the
solenoid must be replaced.

7.2.6 Fuses

Fuses are inserted in electrical circuits to protect the circuits from damage due to overload or short
circuits. Fuses are a "weak link" in the circuit. They contain a metal link designed to melt when a
certain current value is exceeded thus opening or disconnecting the wiring.
Once a fuse blows or melts it must be discarded and replaced with a new fuse of the same value.
Since the function of the fuse is to protect the circuit, NEVER attempt to repair the protective de-
vice by bridging or replacing it with one with a higher current rating.
Electrical testing of these devices is simple, as the device either conducts current (and is therefore
functioning) or the device is open and is therefore faulty Use an ohmmeter to check for continuity