ALIGNMENT PROCESS: STEP BY STEP EXPLANATION

Special thanks to Mr Robert Richard, Mechanical engineer specialised on marine engine installation.

PART 1: INSPECTIONS

1. CONDITION OF THE ENGINE BED

– The engine bed must have the same inclination angle as the propeller shaft.

– The support pads where the bearings will sit must be solid, strong, dry, free of moisture, and cover the entire surface of the support base.

2. Condition of the engine mounts

– Inspect the supports for corrosion or wear. If they are significantly deteriorated, they must be replaced.

– Some supports may appear to be in good condition, but over time, they may lose their original height and no longer function correctly.

3. Condition of the SHAFT

– Check that the shaft is not bent and that it rotates smoothly without any rough spots.

– A well-aligned shaft must be centered within the bearing.

4: Cutlass Bearing

– Inspect the stern tube bearing to ensure it is not worn.

5: Stuffing Box

– Check the condition of the stuffing box.

If any of these elements require repair (or are questionable), they should be addressed first. Attempting alignment without resolving these problems can be a waste of time.

Before starting, ensure that the boat has been in the water for at least 24 hours.

PART 2: ALIGNMENT

1: DISCONNECT THE SHAFT

Disconnect the shaft and verify its free movement.

2: CHECK THE CONDITION OF THE COUPLING SURFACES

– If rust is present, sand and clean the surfaces.

3: CENTER THE SHAFT

– If rust is present, sand and clean the surfaces.

4: ENGAGE THE GEAR

Put the engine in gear (first gear) to ensure the transmission does not rotate during the alignment check.

5: ALIGNMENT

Start leveling the engine using the lower nut of the leveling studs.
Use the rear supports to adjust concentricity. The front supports are used for finer adjustments.
If a support requires more than 7mm of shimming, it is recommended to use shims for added safety and durability.
Once acceptable leveling is achieved, slide the coupling face of the shaft to the transmission until contact is made.
Check if a 0.003-inch feeler gauge fits evenly around the perimeter. If it fits in some parts and not in others, it means the alignment has not been done properly.
Visualize the coupling face like a clock: imagine the top, bottom, and sides as the numbers on a clock.
If the gap is wider at 9 or 3 o’clock, the engine needs to be adjusted laterally (which can be more challenging with larger engines). A gap at 12 or 6 o’clock will require an adjustment up or down.
Once the adjustments are made, continue verifying the gap. With each check, rotate the coupling 180 degrees and verify again. If the gap moves, one or both couplings might be deformed and need to be repaired before continuing with alignment.
Adjust until the feeler gauge fits evenly around the perimeter.

6: FINAL TIGHTENING

– With the engine leveled, insert the washers and tighten the supports with the upper nut.

– Be careful not to disturb the leveling or over-tighten the supports while securing them.

– Use appropriate tools like open-end wrenches and “gooseneck” socket wrenches.

– Typically, three wrenches are needed: one for the upper part, one for the lower nut of the leveling bolt, and another to tighten the upper nut.

7: CONNECT THE COUPLING WITH THE SHAFT

– With the supports tightened, check the alignment one last time and tighten the coupling.

– If possible, tighten the bolts sequentially, alternating between each one, using a torque wrench to ensure the correct torque is applied.

ALIGNMENT PROCESS: STEP BY STEP EXPLANATION