Tecumseh V-twin - Voltage Regulators; Fuel Shut-Down Solenoids; Low Oil Pressure Sensor Testing

5-7
VOLTAGE REGULATORS
If a known good or load tested battery fails to maintain a
charge, the charging system and the regulator can be
checked using a voltmeter. Set the voltmeter on the 0-20
Volt D.C. scale and connect the probes across the battery
terminals. Note the battery voltage. Start the engine, the
voltage reading should increase from the noted battery
voltage but not exceed 15 volts D.C. If no voltage increase
is noted, proceed to make an A.C. voltage check using
the applicable procedure. If the battery voltage exceeds
15 volts D.C., or the proper minimum A.C. voltage is noted
during the check, replace the regulator. (Illust. 5-8)
FUEL SHUT-DOWN SOLENOIDS
If the engine is running, the solenoid(s) can be checked
by removing the electrical plug-in at the base of the
solenoid. Almost immediately the engine should shut
down, if not replace the solenoid.
Test the solenoid off the carburetor by applying 12 volt
D.C. from the battery positive terminal to a solenoid
terminal. Connect a jumper wire from the metal housing
(or other terminal) to the negative battery terminal. The
plunger should retract the full travel distance. Disconnect
the negative jumper lead and the plunger should return
to the extended position. (Illust. 5-9)
5-9
5-10
5-8
D.C. OUTPUT - RED
FUSE
YELLOW
RED
GREEN
SWITCH
LIGHT
SOLENOID
MAGNETO
GROUND
AMMETER
REGULATED
D.C. OUTPUT
NOTE: D.C. OUTPUT MUST BE DISCONNECTED TO
PERFORM A.C. OUTPUT TEST.
BATTERY
LOW OIL PRESSURE SENSOR TESTING
Test the sensor on a running engine using an ohmmeter
or continuity tester. Disconnect the wire lead from the
sensor. Connect one lead of the tester to the sensor
terminal and the other to an engine ground. An open
circuit should be found with the engine running and
continuity should exist when the engine is shut off. If
continuity is found with the engine running or the tractor
oil pressure indicator light is on or comes on at low engine
RPM’s, remove the sensor and check engine oil pressure
with a master oil pressure gauge. The oil pressure of a
running engine should be above 10 p.s.i. (.700 bar). If
below 10 p.s.i. (.700 bar), an internal engine problem
may exist. (Illust. 5-10)