Removal of Prop Coupling - To Remove Engine
 

I am trying to remove the engine and thus must disconnect it from the propeller shaft. I have never done this before and can't seem to figure out how this is done. I also don't understand what is going on under the metal, I removed 1 square screw that seems to hold the prop shaft, 3 bolts that were rather long and pointed to the forward of the boat, and 6 more that were shorter and connecter to the reversing gear(I think). It seems as if none of those will allow me to remove the engine from the shaft. I see the 3 huge 7/8" nuts that go around the Coupling, I tried to remove them and have no luck as they are very shallow. Are these the nuts in the manual mentioned as 1 1/8" with "be sure to fold back the tabs of the restraining washer before loosening the nut." this is found in the major overhoue section part 3, step 2.i don't have the slightest clue what the tabs would be or how to remove those if there's something holding those nuts in place. How do I get this thing off?? It's the only thing keeping the engine in place
Attachment 14452

First, I'd put the 6 bolts back into the reversing gear - they just hold the aft seal and the main bearing in place. Leave them for now.
I've never seen a coupling like that. What is the OD?
Most A4 engines end in a flange thats 3.5" OD and about 5/16 thick. The 3 long bolts usually go through the coupling and into the transmission flange.
Can you feel a ring on the fwd face of your coupling? Perhaps that coupling is covering the usual flange.
I think you're going to have to remove those bolts with the 7/8" heads. I'd do this by buying a new 7/8" 6 point socket, then grinding down the nose so the teeth go all the way to the end.

I see, thanks for the advice. I haven't found a ring but I'm not really sure where I'm looking, I'll try the trick with grinding down the socket, maybe that will help, it's just so shallow there's so little to grab onto

This is, in my opinion, the worst job on the boat. You need to put a lot of power into a cramped space against rusty parts to get a very small amount of movement - and completing this is not the point of the effort in the first place, it just opens up the door to the real project.

And your situation is further "enhanced" with an unusual shape and style of coupling, with mysterious huge bolts with flats that are peculiarly blocked.

My ponderings:

(1) Typically, these assemblies feature an engine-side coupling with threaded holes, and a shaft-side coupling through which the bolts pass to screw into the engine-side coupling. What were your three fore-and-aft bolts screwed into - nuts, or threads? If threads, well, that was probably the coupling on the engine side. Check that out carefully - those bolts hold the two pieces of this assembly together, but either rust has occluded the boundary between them or we just can't see the engine side in this photo. If you can't see anything, it isn't a crazy idea to run the engine in gear, if you can, for a while, with the bolts out to see if you can worry the two parts apart.

(2) The rings obscuring the flats in those large bolts - what the heck is their purpose? Are they part of the fasteners or part of the casting? The look like a tamper-resistant feature. Are they, possibly, removable by drilling with a hole saw or segmenting them with a carefully-placed Dremel bit? Perhaps they exist as part of a final fine alignment to balance the shaft inside the coupling. That's fussier than the standard A4 tolerances but perhaps it's a thing in more precise machinists' circles (from which I have been banned).

(3) Three holes in this coupling - is this a V-drive? I had thought that most other A4 transmissions have four coupling holes. V-drives are good-news/bad-news arrangements, mostly good news over an A4's maintenance history but somewhat bad news in this instance because of the very limited access under the transmission. At least in my installation.

My opinions/guesses:

• I think the unusual hunk of iron is an after market vibration damper and the three long bolts you removed are what held it in place.
• I also think the damper and coupling are rusted into place. I would make an effort to pry it loose with whatever assemblage of wood blocks and pry levers give a good advantage.
• If the pry effort does not work, out comes the Sawzall to cut the shaft.

Standard straight drive coupling flange has 3 threaded holes. Reduction gear uses a splined connection, not sure about the V-drive.
With the 3 long bolts removed, I'd be tempted to see if I could get the shaft and coupling to turn while holding the flywheel (engage fwd gear).
Sure would be nice to see what the fwd side of that coupling looks like! Perhaps a smartphone and a mirror?

That coupling appears to have been made by "Federal Motors Co" which is currently known as "Federal Marine Transmissions Inc." Their phone # is
708-352-2200. I'd start there in trying to figure out how to remove it. Their website shows an x-ray view of what's inside, which may also help in figuring out the puzzle.
Tom

In support of Thatch's excellent research,

http://www.federalmarinetransmissions.com/100101.html
http://www.moyermarineforum.com/foru...ead.php?t=3415
and
http://www.moyermarineforum.com/foru...ead.php?t=5576

Here's a picture of the other side, for the most part the shallow nuts are stripped, it seems as if they won't budge, I can see some kind of metal shaft going under the Coupling cover thing, if I lift the engine with my arms it will lift 1/2"and then hits something and pulls on the coupling/prop shaft as well
Attachment 14454

If you can't get it apart, take a sawsall to the shaft and cut it away, then work on the coupling in the comfort of your garage after you pull the engine. Prop shafts are cheap compared to the aggravation of working in tight quarters.

I believe that you are about three quarters of the way there in the process of separating the engine from the coupling. If you take a quick look at the aft end of the "rotating Moyer pin-up engine" you will see that there is a large nut on the back of the engine output flange. It will involve sliding the prop shaft aft about 3/4" to gain the clearance needed to lift the engine.
Tom