Alignment help

I used a dial indicator and checked the shaft in two places between the strut and shaft log plus I checked again at the shaft taper and the shaft appears to be perfectly straight. I'm not able to check the straightness of the shaft up by the coupler because I can't turn the shaft when the couplers are tightened and if I leave them loose, just touching the shaft skews the measurements.

The problem I currently have is the coupler gap follows the shafts coupler and is about 0.013" more than the opposite side. I've gotten the engine alignment so that the same gaps follow their respective position on the coupler regardless of orientation (hope that makes sense). The shaft coupler wiggles a bit which I think may be the primary culprit here.

What are my options? Would a new coupler fix the problem?

John,
Chris is correct that it would be a good time for a ARE shaft system. The coupling on the shaft is a heat shrink (.000" to a -.0005") interference fit. It should not be loose. It also sounds like the shaft is bent since the gap between the coupling faces follow the shaft rotation. I would also question your engine to prop shaft alignment since it should turn freely when the coupling it tightened up.

How's the strut to the log alignment? Remember, alignment starts at the strut and then you move forward.

John,
The coupling should not "wiggle" on the shaft at all. The coupling is worn from fretting due to misalignment. An interference fit is when the coupling is locked onto the shaft after it cools. Heating the coupling expands it so it will go onto the shaft. You have missed what an interference fit is. The coupling is trash. The "happy place" or "sweet spot" is when the alignment of the strut is correct so the shaft spins freely {coupling halves not bolted) in the strut and is centered in the log.