Severe Vibration in Gear

[john540]

While attempting to execute a back-and-fill in a narrow fairway (it seemed narrow at the time at least!) last week, my transmission wouldn't shift out of reverse! After fighting it a bit, it finally shifted, so I promptly docked the boat. I couldn't figure out what had happened, but it seemed to shift just fine repeatedly at the dock. I motored over to the fuel dock, and eveything seemed fine, but when I left the fuel dock, there was a SEVERE vibration when I put the transmission into gear (forward or reverse) My immediate thought was that the prop shaft strut had cracked or broken. I limped back to the marina at idle (very little vibration at idle), and parked the boat. Any guesses what the problem was?
P.S. Supposedly, it's fixed, I'll find out in a few days when I return.

[Cotemar]

loose motor mounts. Simple fix. Tighten every motor mount bolt, then tighten again

[captain465]

Sounds like you might have picked up a piece of line or a plastic bag on the prop. The vibrations had nothing to do with the shift problem.

[john540]

Originally Posted by captain465

Sounds like you might have picked up a piece of line or a plastic bag on the prop. The vibrations had nothing to do with the shift problem.

Correct, the diver found a line wrapped around the prop shaft. I thought of engine mounts also, but it seems that that affects it more in neutral?