OMC 1984 3.8L engine mounting screws lose

[dlogvine]

I have an OMC stringer sterndrive 3.8L 4.3. The screws on the left side mounts are mostly lose and the holes are full of dry rot with rust. I can clean the holes wth a wire brush, but not sure as to how to fix the new screws in the holes. Should I use something like liquid nails or some other filler to fill up the hole and glue the screws inside? I thought about drilling a larger holes filling them up with wooden dowels and drilling the screw holes in them, but it would be difficult without removing the engine. Any suggestions?
Thanks

 

[Scott Danforth]

you will have to remove the motor to attempt any kind of repair. most likely you will find the mounting blocks have long since rotted away. however if you perform a few test drills into the block down low and the wood shavings come out clean, light colored and dry, then you may get lucky. in that case, you can drill larger and epoxy a slug of wood in there.

However if your test drills come out with wet, dark shavings, the motor needs to come out, the blocks need to be removed, and your stringers and transom will need to be inspected. if you keep the stringer drive, the good news is there really is not much to alighning the motor (its all one assembly). the other good news, if you find your transom is rotten and you want to move away from the stringer drive, you can at this point rebuild the transom and change over to a mercruiser or volvo.

do some searching in the hull repair forums. this is not an OMC issue, it is however a hull issue.

 

[jerryjerry05]

Follow Scotts directions about testing the whole stringer for rot
IF??? It's only around the area of the screws(hope,hope, hope).
I've fixed that problem with a product called Git Rot.
It can be used while the engine is still in the boat.
Just make sure the stringer is sealed up so none of the liquid leaks out.
I used 2" wide masking tape to cover any holes and covered the area around the stringer.

I think the Git Rot says it can be used with wet wood but I wouldn't .
If the boats up for the winter? A small fan and a small bilge heater will dry out the wet eventually.
Might take 3-4 months.

If it's wet all the way to the hull then replace the stringer.

 

[dlogvine]

thank you, will check how much the wood is deteriorated and will use the git-rot kit if the damage is not too extensive. i think there is still hope, since the right stringer is ok and holds the screws.

 

[Scott Danforth]

again, if the wood is wet, it will hold screws for years, however is slowly rotting.

on my '84 Avanti, the motor mount boxes were filled with water, only found when I pulled the motor for an oil pan fitting leak. lag bolts were rusted off. tried drilling, found water logged wood.

I ended up with a complete transom replacement, motor box, stringers, and section of floor.