Sterndrive Engine Alignment

[George Van Parys]

The down and dirty of this job is to verify if the engine and drive shaft are in alignment. Before you start this job as a new mechanic or Do-it- yourselfer, I need to warn you that it is not as simple as it looks, I've seen too many of these done incorrectly and the out come is an engine pull. So, if your ready to go ......

Warning: The tool that is used can be rented from some tool rental places but be careful because there are now two tools on the market. The new style tool will work on the older motors but the old style tool will not align new style motors properly.

The first step is to get ready to remove the drive by putting the unit in forward gear, (reverse gear for counter rotation) and removing the trim pin and nuts that connect the drive to the trim system. Then either support the drive from above or place blocks under the sterndrive so that the u-joint driveshaft is inline with the crankshaft of the motor and not cocked up or down, or side to side. Place 3ft. long 2x6 boards on the ground so you can slide the drive off and on without much lifting. At this point you need to:

Tip #1) Get the manual and do it like they tell you to do it.

Tip #2) Always have someone check it who has done it before.

Tip #3) Look carefully at the spline and the coupler for wear. If the grease dried up and the spline ran dry, have a professional look at it to see if you should reassemble. Usually the coupler is the first to wear when they run dry. If the spline teeth in the coupler look "pointy" or half of the spline tooth is worn away, replace the coupler.

Tip#31/2) If you have good alignment but the couple has dry teeth upon inspection, tap the engine over 180o, to see if the coupler is warped and or warbling and then recheck the alignment. If the alignment has changed after cranking the motor 180o, the coupler is shot.

Tip #4) Always use M/C Spline grease and no other product on the splines.

Tip #5) This is a good time to hand grease the gimbal bearing. Spin it with your fingers, before you grease it. If it feels rough or the cage feels loose, replace it , don't waste your time greasing it. ( the same for the U-joints) If all is well spin the bearing while greasing to fill more completely.

Note: You do not need to use spline grease in the gimbal or u-joint bearings.

*Are there signs of water and or rust in the bellows? If so fix that problem , before reassembly.
*Are there rust stains on or around the shift cable pocket? Look for and fix that leak, before you need a new shift cable too. ( don't forget to check for a loose core plug under the upper stern drive decal....)
* Do all your hoses behind the bell housing look good? Especially check the water hose between the bell housing and the transom assembly for cracks.
*Clean the areas your going to glue the rubber seals and o-rings into, with a good cleaner and install new seals and o-rings and let the glue dry thoroughly, before drive installation. Always install new o-rings and gaskets. On sterndrives that require a sterndrive gasket, NEVER install two sterndrive gaskets or glue them in place., in an attempt to stop leaking. If you rip a sterndrive gasket while installing the drive, get a new one.

Tip #6) Even if you didn't need to re-adjust the alignment, re-torque the motor mounts. Check and reset the locking washers on the motor mounts when your done doing the adjustment.

Alignment tool updated

That old alignment tool you got from uncle Joe, doesn't fit your new M/C engine.
But you can take it to most local machine shops, and they will fix that, for a small fee. This modification will still let you use the tool on the older motors too.
No. 92-9
A. ENGINE ALIGNMENT TOOL MODIFICATION

All Alpha One Gen II Models

An engine coupler change will take place on these model engines sometime in August, 1992. Because of this change, the current Alignment Tool (91-57797A3) will not properly align the engine. Please have your current alignment tool modified as shown in Figure: 1, or order a new alignment tool.

Use the first step on the tool as reference point "X".
1) The shaded area of the tool must be machined off. Machine the 1.150 in. (29.21 mm) diameter
(a) back for a total of 2.750 in. (69.85 mm)
(b) from reference point "X". Finish the edge of the new step as shown by (c).

2) Measure from reference point "X" to the end of the tool. This should not be longer than 2.200 in. (55.88 mm) (d). If the step is longer, remove material from the end (e) until the step is 2.200 in. long. If material was removed, put a .060 in (1.5mm) x 45 degree chamfer on edge (f).

NOTICE!! The modified 91-57797A3 tool or the new tool 91-805475Al will align all current Alpha One or Brave models as well as all older engines that used the older 91-57797A3 tool

New Tool
91-805475A1 Alignment Tool