Specifications

48
L510010-04
ENGINE MAINTENANCE - 11
ENGINE ALIGNMENT
CAUTION
Engine must be properly aligned, or vibration, noise
and damage to the transmission output shaft oil seal
and bearings may result.
IMPORTANT: Engine alignment MUST BE
RECHECKED with the boat in the water, fuel tanks full
and with a normal load on the boat. Engine must be
aligned so that the transmission and the propeller shaft
coupling center lines are aligned, and coupling faces
are parallel within 0.003 in. (0.07 mm). This applies
to installations with solid couplings, as well as fl exible
couplings.
1. Check the mating surfaces on the transmission
and the propeller shaft couplings. Make sure
they are clean and fl at (Figure 11-26).
Figure 11-26 Shaft Mating Surface Check
3. Check that the coupling center lines align
by butting the propeller shaft coupling against
the transmission coupling (Figure 11-28). The
shoulder on the propeller shaft coupling face
should engage the recess on the transmission
coupling face, with no resistance.
Figure 11-27 Centering Prop Shaft
B
B
A
A
2. Center the propeller shaft in the shaft log as
follows: (Figure 11-27)
• Push down and then lift the propeller shaft as
far as it will move, then place the shaft in the
middle of the movement.
• Move the shaft to the port and then to the
starboard as far as the shaft will move,
then place the shaft in the middle of the
movement.
• With the propeller shaft in the middle of the
shaft log, align the engine to the shaft.
IMPORTANT: Offset misalignment conditions must be
corrected prior to checking for angular misalignment.
NOTICE: Some propeller shaft couplings may not have
a shoulder on the mating surface. On these installations,
use a straight edge to check the centerline alignment
(Figure 11-29).
Figure 11-28 Shaft Mating Surface Check
OFFSET
MISALIGNMENT
ANGULAR
MISALIGNMENT
PERFECT ALIGNMENT
COUPLING FACES ARE PARALLEL
WITH DISTANCE BETWEEN FACES
EXACTLY THE SAME AT ALL POINTS