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Chief Engineer · 29-11-2010, 17:49

I gotcha now. I thought I was looking at an engine that had had the propeller shaft removed.....

Still no certain of that bolt...can you determine if there are threads in the end if the shaft?

delmarrey · 29-11-2010, 19:26

The 90º hole has a standard set screw in it, which is wrong to start with. Set screws for couplers have a square head with a wire hole thru the head. The hex socket set screws can come loose and fall out, allowing the prop shaft to slide out of the coupler just at the worst moment (Murphy's Law).

As for the end, if that hole is threaded then that bolt will not go in all the way due to the unthreaded portion of the bolt, unless part of the threaded hole is counter bored deep enough to except the shank of the bolt.

INHO I would pull the coupler off the v-drive/shaft to see if the prop shaft end is threaded and put in a sq. hd. set screw (sample picture below but with a safety wire). Actually there should be two, either at 90º or 180º.

The end hole could possibly be a jacking hole to force the shaft out of the coupler and the bolt came from somewhere else or is a lost bolt.
Take a mirror and look around under the trany/motor for an empty hole.

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Blue Stocking · 01-12-2010, 07:57

The wear on that allen screw does not indicate its use as a locking screw.
My money would be on it being from a dis-used Drivesaver.

perchance · 01-12-2010, 08:26

Note the cap on the end of the coupling like a thick flat washer held in place by hex head cap screws. Sorry shcs.

delmarrey · 01-12-2010, 09:36

Quote:

Originally Posted by perchance

Note the cap on the end of the coupling like a thick flat washer held in place by hex head cap screws. Sorry shcs.

I noticed it also, but would be cautious about removing it due to the rust. I'd remove it after the coupler were off the shaft. But it might only be a thrust plate for the (possible) jacking screw. Can't tell w/o it apart.

perchance · 01-12-2010, 14:27

It may have to come off to use a puller on it

Sailmonkey · 01-12-2010, 14:36

Guys, this isn't complicated.

The shaft passes though the transmission from below the engine. the front of the engine is facing aft in the boat, and the engine is above the shaft. Since the shaft passes though the transmission the coupling is put on the shaft after it passes though. Since the coupling is put on the shaft in such a way that allows the shaft to be tapped for a bolt, it is. The bolt goes through the coupling and screws into the shaft, it is meant to retain the shaft, to prevent it from backing out when operating astern.
Run a tap into the hole, replace the bolt if you want with something stainless with some blue loctite and carry on with life.

the link is to a similar type of hurth gear.

Marine Transmission Dealer, Hurth Transmissions