MD7A Rebuild

"I am planning on having my MD

"I am planning on having my MD7A rebuilt over the winter months. In preparation for this, I will be removing the engine from the sailboat in the next two weeks. It is connected to a 110 saildrive, I assume via a splined shaft.

The engine has only two motor mounts at the front, and is supported at the back through the connection to the saildrive.

Is anyone aware of any particular pitfalls to avoid during the removal of the engine?"

"I went through the same job l

"I went through the same job last year with a MD5B/110S and I think your procedure would be similar. There are three mounts, the two you mentioned and one behind the sail drive. Only detach the engine mounts and leave the saildrive mount alone. When you pull the engine back from the saildrive the rubber coupling ring will fall off the engine output and saildrive input shafts. These shafts are castellated and fit into notches in the rubber coupling ring.

It is difficult to align the ring and shafts when installing the engine back in the boat. I placed the ring on the saildrive shaft, aligned everything to mate properly then loosely secured the ring to the saildrive shaft with a thin nylon cord looped around the ring and saildrive. I then slid the engine to the saildrive, checked that everything was mated, pushed everything together then cut the cord and pulled it out before bolting. This procedure worked great for me. Hope you find it useful.

If your boat is out of the water, you may want to replace the saildrive rubber gasket ring at the same time. The job is easy with the engine out. Good luck."

"Gordon

Thanks for your ver

"Gordon

Thanks for your very thorough response. I'm sure that it will be most helpful.

There seems to be some kind of adapter piece between the block proper and the saildrive. As the "books" I have on the engine make reference to either a saildrive or a "reverse gear" device, I am assuming that the piece is necessary for the saildrive mating and that a different piece would be used if the engine was to be connected to the reverse grar and regular driveshaft. With this in mind, I gather that I should make the disconnect at the saildrive joint rather than at the engine block. Make sense to you?

And yes, I had planned on replacing the saildrive rubber gasket, as the boat will be out of the water all winter. I have no idea what the life expectancy is for the rubber, but I have had the boat for 9 years, and I would be willing to bet that it had not been replaced for at least 10 years before that."

"David

You are correct, the

"David

You are correct, the extension is the connector from the engine to the saildrive. A reverse gear would go there on a shaft drive boat. The rubber connector ring I mentioned is inside the connector. I think you can see all this if you look under the connector with a mirror and light. I could be wrong on this but I vaguely recall having a look before I started surgery. Anyway, detach the engine at the saildrive end of the connector. Mine had hex head machine bolts at that end while the engine end had cap screw bolts that were rusted and would have been difficult to remove in the boat.

Volvo recommended replacement of the rubber gasket after five years of service (owners manual). However, mine is original in my 1980 boat! Many have told me that they will go a long long time and will usually start weeping before a serious failure. Several marine engine people said they seldom have seen the need to replace them. Most said that any replacement they have done was necessary because the inside ring was badly rusted. I’m replacing mine this winter – why push it! I would have done mine at overhaul but my boat was in the water when I pulled the engine.

Gordon"