motor mounts & stringer plates

[brookesmith]

I had all motor mounts changed by our yard here. Nice job.
But the other day I removed a plywood flooring next to the starboard stringer and touched the big nut on the bolt that holds the major plate that the motor mounts mount to and the nut was rusted off. There are only two bolts that hold this plate to the stringer and the motor mounts are on top of the plate. Not sure i should try to change these even one at a time as the weight of the front of the engine is pressing down on this bolt. I'm thinking of drilling another hole through the plate and stringer and then after securing that with a 3rd bolt that I should be able to remove the rusted bolts one at a time.. Anyone had to replace those stinger bolts before????

[DougSea]

I had all motor mounts changed by our yard here. Nice job.
But the other day I removed a plywood flooring next to the starboard stringer and touched the big nut on the bolt that holds the major plate that the motor mounts mount to and the nut was rusted off. There are only two bolts that hold this plate to the stringer and the motor mounts are on top of the plate. Not sure i should try to change these even one at a time as the weight of the front of the engine is pressing down on this bolt. I'm thinking of drilling another hole through the plate and stringer and then after securing that with a 3rd bolt that I should be able to remove the rusted bolts one at a time.. Anyone had to replace those stinger bolts before????

I don't like the idea of "extra" holes unless they are really needed. Can you find some way to brace the engine, perhaps some oak blocks/shims, to allow you to secure the engine as you remove the bolt?

[jleonard]

If you can find/beg/borrow/steal a large clamp you could change the old ones out that way.
However, not agrreeing with DougSea, I would not be opposed to drilling 2 new holes and using 2 nice new bolts etc., then removing the old stuff.
Taking care to clean the old holes out and sealing them with epoxy afterward to keep the stringer from taking in water.

[brookesmith]

Thanks for both replies. I think I might drill two more holes diagonally from the existing bolts and seal everything really well. To me there should have been 4 bolts holding this plate to the stringer anyhow. After installing the new bolts I should be able to replace the old bolts without anything shifting. Another person I spoke with suggested large clamps. I don't see how I can get them far enough on metal to be effective. Thanks DougSea and lLeonard..

[damar]

I don't know the motor mount history on the Classics but I have found some engines rested on steel angles (1 for each motor mount) that were bolted to the inboard side of the stringers. Each angle was fastened to the stringer with 2 each angle 1/2 st stl. rods - threaded at both ends. In other words 8 of these rods held up your engine. And then at some point in time the stringers - I think - were brought inboard and the engine rested on top of the stringers. A friend of mine has a 40 classic which is this way. Mine is a 36 and the engine rests on the angles.
When I got our 1979 36 I new before I bought it - it needed a lot of work. These steel angles were rusted. I am fortunate to have small aluminum A-frames that I rested on top of each stringer. This had a beam across the top. I wrapped a chain around the beam and with a com-a-long I picked up the forward end of the engine first. Prior to this I disconnected the shaft coupling from the engine coupling and removed the top nut of each of the 4 motor mounts. I did some changes - mainly replacing of hoses in the exhaust system. In other wards I did not have the exhaust connected either.
I then picked up the front of the engine just high enough to clear the motor mount studs and then removed the 1/2" rods that held the angle to the stringer. I then had the forward angles drilled for 2 more rods, then had them sand blasted and painted. I also cleaned up the engine mounts, (wired brushed, etc.) I replaced all the 1/2" rods with 1/2 stainless steel hex hd. bolts. I remounted the front angles, set the front end of the engine back on the rebuilt angles. I then moved the A-frame to the aft end of the engine and lifted up the aft end of the engine like I did for the front mounts. Of the 8 original 1/2" rods - 2 were corroded down to nothing. Three other ones were not all that great of shape. I now have 16 ea. 1/2" bolts holding up the engine.

[brookesmith]

Thank you for this reply. Our boat is a 1979. Not sure how I can support the front of the engine to remove the brackets. I'm going to go to the boat and stare some more..

[psneeld]

I replaced the motor mounts on my sportfish by using 4x6's that spanned the cabin (at least to near were the cabin floor met the sides of the boat, and used 1/2" threaded rod with chain to an engine lift ring (or could be wrppped around the engine). I lifted 3208 Cats with one finger using a regular box wrench to the nut on top of the threaded rod. Piece of cake.

[brookesmith]

THAT IS A REALLY COOL IDEA THAT COULD WORK ON MY BOAT. THANKS. I just hope it gets hauled from the covered slip today and then doesn't get blown over by IRENE in the jack stands.