Section07ELECTRICALSYSTEM
Subsection 01 (IGNITION SYSTEM)
The unregulated AC current from the magneto
generator coil supplies the Multi-Purpose Elec-
tronic Module (MPEM) for its ignition functions.
Multi-Purpose Electronic Module
(MPEM)
The Multi-Purpose Electronic Module (MPEM) is
powered with DC current from the battery.
AC current from the magneto is supplied to the
MPEM for its ignition functions.
The MPEM is responsible of the following electri-
cal functions related to the ignition system:
– input voltage of ignition coil
– ignition timing curve
– engine rev limiter.
Ignition Coil
Ignition coil induces voltage to a high level in sec-
ondary windings to produce a spark at spark plug.
The ignition coil steps up the voltage input from
the Multi-Purpose Electronic Module to high volt-
age current for both spark plugs.
The ignition coil is located in the rear electrical box
located under air intake.
ADJUSTMENT
IGNITION TIMING
Before checking ignition timing with a stroboscop-
ic timing light (dynamic test), it is mandatory to
scribe a timing mark on the PTO flywheel (static
test) corresponding to the specific engine.
Also, the timing mark scribed on the PTO flywheel
can be used to troubleshoot a broken magneto
woodruff key.
CAUTION: The relation between the PTO
flywheel mark and crankshaft position may
change as the PTO flywheel might move on
crankshaft when engine is ran. This will result
in false ignition timing readings. If timing mark
does not align with pointer tool when checking
the ignition timing with an appropriate timing
light (dynamic test), verify timing mark again
(static test) to ensure flywheel has not moved.
NOTE: Do not use the factory mark found on the
PTO flywheel to check ignition timing or trou-
bleshoot any problems.
Scribing a Timing Mark (Static Test)
– Disconnect MAG side spark plug wire and
connect wire to grounding device then remove
spark plug.
CAUTION: Never crank engine with spark plugs
removed unless spark plug cables are connect-
ed to the grounding device.
– Remove PTO flywheel guard.
– Install timing mark pointer tool (P/N 295 000
130) on engine using wing nuts previously re-
moved.
F01H5SA
1
TYPICAL
1. Timing mark pointer tool
– Install and adjust a TDC gauge (P/N 295 000
143) in MAG side spark plug hole.
146 smr2005-057
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