Sea-doo 2003 GTI LE RFI, Shop Manual

Page: 516 / 779

Section 12 ELECTRICAL SYSTEM
Subsection 02 (IGNITION SYSTEM (CARBURETED ENGINES))
12-02-2
SMR2003-035_12_02A.FM
787 RFI Engines
Crankshaft Position Sensor (CPS)
The CPS is an inductive speed sensor located on
the magneto housing and is working in conjunc-
tion with a 60 teeth ring gear which has 2 teeth
missing on the gear. The inductive sensor regis-
ters the 58-tooth sequence.
An AC voltage is generated by the sensor and is
sent to the ECU to calculate the crankshaft posi-
tion and the engine speed.
1. Crankshaft position sensor (CPS)
Ignition Coil
Ignition coil induces voltage to a high level in sec-
ondary windings to produce a spark at spark plug.
GTI and GTI LE Models
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.
GTI LE RFI Models
The digital inductive ignition system on the RFI
models allows the spark plugs to spark indepen-
dently on each piston stroke.
CAUTION: Do not interchange spark plug ca-
bles. Reversed spark plug cables will not allow
the RFI to run and will cause backfires.
MULTI-PURPOSE ELECTRONIC
MODULE (MPEM)
717 and 787 RFI Engines
The MPEM is responsible of the following electri-
cal functions related to the ignition system:
– ignition timing curve
– engine rev limiter.
For the other functions of the MPEM, refer to IN-
STRUMENTS AND ACCESSORIES section.
787 RFI Engines
The MPEM is also used with the Rotax Fuel Injec-
tion system.
The RFI models use a Digital Inductive Ignition
system. The Bosch ECU controls the ignition tim-
ing and dwell time. It receives input from the CPS
and signals the ignition coil when to fire.
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 fly-
wheel mark position and crankshaft position may
change as the PTO flywheel might move/tighten/
loosen on the crankshaft. As an example on
threaded flywheels, when the engine is accel-
erated out of water, PTO flywheel may tighten
then loosen when the engine is decelerated.
This will result in a false ignition timing read-
ing. Always verify PTO flywheel mark position
before checking ignition timing with an appro-
priate timing light. If mark does not align with
tool, repeat static test to ensure flywheel has
not loosen or moved before changing the igni-
tion timing.
NOTE: Do not use the factory mark found on the
PTO flywheel to check ignition timing or trouble-
shoot any problems.
F07H0CA
1
www.SeaDooManuals.net