Something to check before following Irish Ramblers advise on removing the coupling from the shaft.
I have a Bene, and removed the coupling two years ago to replace the shaft seal
(I have a Vetus seal on mine).
The coupling is secured to the shaft by a bolt which threads into the end of the shaft. You cannot see the bolt, but after disconnecting the coupling from the gear
box side, slide the shaft aft a couple of inches, and you can feel the bolt head
inside the coupling.
Bit of bother this as you have to somehow lock the shaft to stop it rotating while removing the bolt.
Did mine with the boat on the hard
, and used a length of baulk of timber wedged under the prop to keep the shaft from turning.
If you are in the water, put a couple of bolts back in the coupling flange, place a spanner over one bolt with the shank of the spanner jammed under the second bolt to prevent the shaft turning. This is a lot easier with two pairs of hands.