Engine Alignment

@Thomas Sullivan

My first thought is if your alignment was truly 3/16" off there's no way the prop shaft would go into the coupler without bending the shaft or loosing the coupler bolts a lot.

Was a new cutlass bearing installed at the time of reinstalling the trany?

If so the tighter tolerance will intensify a mis alignment compared to a worn bearing which gives a false sense of alignment.

How long is your aluminum test shaft? It's own weight could very easily cause an inaccurate read.

You'd probably be better off using your auctuall shaft (after it's been confirmed straight within 2 thou of perfect or a full length test shaft)

It's also possible that there could be a slight bend in your strut .

The strut could also have a bent mount bolt or even a worn out or disturbed shim.

As far as using feeler gauges , if you already know your alignment is miles off then no point to use feelers until you start to get into the ball park .

Once into the "ball park" put all the coupler bolts in but don't tighten them all the way .

The index ring on the fwd face of your coupler should be into the tranys output flange enough to hold the coupler (with the prop shaft installed in it) in place.

Now find the feeler that fits snug in the gap . Now you can make adjustments to your engine mounts .

While the boat is out of the water, do your initial alignment without the stuffing box or its hose in the mix so you can visually see If the prop shaft is centered in the shaft log.

There's no point in getting an alignment between the strut and engine only to discover that the shaft is too close or even rubbing on the log.

Once you achieve a nice alignment between engine and strut while the shaft is also centered in the log , reinstall the stuffing box and hose.

When the boat is back in the water and things have settled, recheck/ adjust the alignment

Thanks Jeremy! The test shaft is 12" long and fits very snug in the cutlass bearing. I got the alignment pretty close before haul out - but with the bad coupler. The shaft log looked like it had plenty of clearance around the shaft (looking from the outside anyway). I thought it would be a good idea to start with a short test shaft so that there wouldn't be any load on the strut and I wouldn't be introducing any flex in the shaft. I'll pull the hose and try the shaft like you suggest.

Thanks again,

Tom

The other thing to remember is the boat is probably out of kilter being blocked and stands on the hard. Doors dont work right windows etc when they are out of their element. I had a 38 that the sliding doors wouldnt hardly move on the hard As Jeremy says do a thorough inspection and measuring of the strut and comparing to your other side and be sure it wasnt tweaked in the past and not remedied. Then if it all checks out do your final alignment IN THE WATER where the boat is in its “relaxed” state after a day or two. If youre still that far out you’ll have to haul back out and see whats going on. Coupler clearance specs after both halves are mated are .003-.005 with a feeler guage around the diameter of the mating surface. Hope this helps you.

Thanks Lee, I pulled the stuffing box as Jeremy suggested and got the shaft pretty much centered in the log. CC only used 4 inches of hose which put the stuffing box almost right against the shaft log. I was thinking of going with 5-6 inches of hose (since I have room) to allow me to move it around after launch to make sure the shaft is still centered and not touching the log after it settles.