My advise.
Reinstall the drive, run it hard for a couple of hours, pull the drive and recheck alignment. You may find that the problem is gone.
you can just remove the bearing ,carefully
It will be tight, using the alignment bar sometimes you really have to give it a good hit with you hand to start it. try using a solid 1 inch bar.
If you take off the 2 o-rings will it slide in? Sometimes, those o-rings can get too much grease under them and will cause your issue. They really only need to be lightly oiled...not greased.
can you obtain a sacrificial yoke , and have a shop cut it 1/8 th inch undersize where the gimbal bearing would ride?
At this point its a guess the coupler was damaged. the bearing has to come out to test the coupler with the shaft.
A should have a new tolerance ring if you need it.
A crude way to do it:
Insert the spare shaft with a short piece of chain and drive it untill it bottoms out. IF the alignment is good it should pull out with finger pressure.
If it needs to be pulled out (slide hammer/ come-along) the rear mounts have most likely collapsed
Now that the bearing is out, can you manually slide it down your yoke to make sure it gets past the o-rings?
Now that the bearing is out, can you manually slide it down your yoke to make sure it gets past the o-rings?
I'd reach in to the coupler, clean it up really well, inside the splines. If you con borrow a boroscope, you can get a good look at the splines and see if you damaged them with the alignment bar. I myself would clean up the splines if damaged with a small file, but that's only if they are just dinged up a small amount. Then clean it up again and test fit the spare shaft and alignment bar. It's probably a bit hard to reach in there but it can be done. Otherwise you have to pull the motor to get at it.
Once you get the motor out, the bell housing comes off and the coupler just unbolts. Really not to bad of a job, The motor is just plug and play wiring, and fuel line removal, shift cable and throttle disconnect. And any cooling hoses riser boots ect... You can unbolt the fwd motor mounts right from the stringer, so as not to disturb the alignment you already have. You should be able to order a coupler right here from I-Boats with your serial number and model number. Personally, I'd pull the old one first and inspect it, see if it can be saved. If damaged to badly, yes replace. If everything was maintained properly, couplers last a long time, I've replaced 2 in my life, just because the owners wanted to have new ones as the motors were replaced at the same time. Both of mine are from1984 and 1985, still working fine.
That confirms our suspicions that the second install of the bearing damaged the coupler. Your going to have to find the correct tool to reinstall the bearing or wait untill the engine is out to use your tool.
"You can unbolt the fwd motor mounts right from the stringer, so as not to disturb the alignment you already have."
Anytime a motor is removed, alignment must be checked. While its out, clean/loosen oil the mounting nuts just incase they need a slight adjustment