Technical data

Section 04 ENGINE
Sub-Section 03 (BOTTOM END)
04-03-4
CRANKSHAFT MISALIGNMENT
AND DEFLECTION
Since it is an assembled crankshaft it can become
misaligned or deflected. Crankshaft can be twist-
ed on center main journal, changing timing of one
cylinder in relation with the other.
1. Main journal alignment here
Counterweights can also be twisted on connect-
ing rod journal on any or both cylinder(s).
1. Connecting rod journal alignment here
Crankshaft Alignment at Center Main
Journal
NOTE : The following checks can be per-
formed with engine in watercraft without
overhauling engine.
To quickly check, without accuracy, if crankshaft
is twisted on center main journal, proceed as fol-
lows :
– Remove PTO flywheel guard.
– Remove spark plugs.
– Insert a screwdriver in one spark plug hole.
– Insert a longer screwdriver in the other spark
plug hole.
– Lay one hand over both screwdriver handles to
feel piston displacements.
– With the other hand, slowly rotate engine by
PTO flywheel.
TYPICAL
1. Lay one hand over screwdrivers to feel movement
2. Screwdrivers in spark plug holes
As soon as one piston starts going up, the other
must immediately go down. Any interval between
strokes indicates a misaligned crankshaft.
Or, to accurately check crankshaft alignment, pro-
ceed as follows :
– Remove ignition housing cover.
– Remove flywheel nut (and magneto rotor for
the 787 engine). Refer to ELECTRICAL SYS-
TEM 08-01 for procedures.
– Install Bombardier degree wheel (P / N 295 000
007) on crankshaft end. Hand-tighten nut only.
– Remove both spark plugs.
– Install a TDC gauge in spark plug hole on MAG
side.
– Bring MAG piston at Top Dead Center.
– As a needle pointer, secure a wire with a cover
screw and a washer.
– Rotate degree wheel (NOT crankshaft) so that
needle pointer reads 360°.
F01D1NA
1
F01D1NB
1
F01D1IA
1
2
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