Re: 1978 omc stern drive
It's gonna be tight in that Beachcraft, specifically if it is the 18 footer. Not a lot of acess over the top of the engine. Just hope the giant hose clamp has it's screw on the side.
Be that as it may, you need to remove the outside retainer ring and loosen the seal from the transom. If you are lucky and it is the original seal, they may not have used any goop to seal it with. That was the case on my '75 unit.
Then crawl in from the cockpit, remove the large hose clamp and pull the seal off the intermediate housing. This is where it get's a little trickier for re-installation. You want to make sure that the mounting groove (on the IH) is clean. You neet to use some kind of mild sealant that will not dry rapidly (I'm sure there are perscribed adhesives for this) to reinstall the seal on the IH.
Lightly snug the clamp then make sure that all the holes line up on the transom. If they do not, loosen the clamp and rotate the seal until they do. Then tighten the clamp. You might use a white paint marker to make reference marks across the IH and the boot. Then you can take your old boot and trascribe a reference mark onto the new seal. This should get you very close so you won't have to tug it around after you glue it and clamp it.
For the transom, I reinstalled my original 30+ y/o boot. I used a small bead of 3M 4200 around the perimeter, using the screw holes as a guide. Then I stuffed some of the 4200 into the screw holes and replaced the retainer ring and screwed them down. Budda Bing! It was done and did not leak.
One last note, if you have the trim feature make sure it is in the full down (front of motor) position.
