Frozen rear engine mounting bolts

[elan86]

Hello gentlemen, I am attempting my first removal of my 4.3 Mercruiser from my 1987 Wellcraft Elan. Most everything has gone well except for my inability to break free the rear mounting bolts. I have soaked them repeatedly with PB Blaster, tapped lightly(and not so lightly) with a ball peen hammer and have been using an electric 1/2 inch Craftsman impact. The bolts are in very good overall condition, no visible corrosion on the tops. Im sure there could be and probably is rust or other factors below.

The reason for removal is a leak that I believe I correctly diagnosed coming from a small outlet on the transom housing. I believe that is the correct term. If you are standing with your knees facing the propeller, the outlet hole is on the lower port side of the housing. There is a matching hole on the starboard side. When the boat is put in the water, water comes in to the bilge at about a gallon a minute, approximately. When I apply a stream of hose water to each outlet hole I get water intrusion on the port side only. No water enters when water is shot into the starboard side outlet hole. The bellows had been replaced just before I got the boat a month ago but may not have been installed correctly. Also I am replacing the starboard lower transom housing bolt and shaft. The threaded shaft snapped from corrosion when my brother in law tried to replace the corroded bolts on the outdrive side of the transom housing.

Anyway, if anybody has any advice or commentary please give! I am now wondering whether I have transom rot and there is pressure on my rear mounting bolts even though I have inspected the outdrive side of the transom housing and dont see or feel any obvious weakness. Thanks, guys.

 

[Fishermark]

Re: Frozen rear engine mounting bolts

An extension and a big breaker bar will work if there is room.

And yes, I would put money on a rotten transom. Sorry.

 

[Howard Sterndrive]

Re: Frozen rear engine mounting bolts

sounds like the transom plate is possibly coming out anyways, so it won't be the end of the world if the bolt breaks if that is the case.

I've had some so bloody tight, I've broken 1/2 drive extensions on 2 occasions.

In both case, my 1/2 impact eventually took the bolts out without breaking them- very lucky...

I know a lot of people think impact tools break bolts, but I beg to differ.
I think a long johnson bar can sometimes be the worst as it applies so much torque from 1 angle... tends to tear a bolt apart from a point off-center opposite where the handle was.

A better impact tool has 4 sets of hammers. 90 degree spaced.

Order new mount springs, if your bolts are cranked down, they will be compressed and cracked for sure.

 

[Bt Doctur]

Re: Frozen rear engine mounting bolts

Worst case you cut the heads off, and making sure there are no gas fumes present, heat the bolt to melt the rubber mount and lift the engine , then remove the remaing piece.If there is some rubbery movement the bolt is frozen to the rubber, if no movement the bolt is frozen in the inner transom housing.
But before you do that ,are you sure is not a bellows or shift boot, the water entry from the relief holes may indicate a rotted/ corroded exaust Y pipe.

 

[elan86]

Re: Frozen rear engine mounting bolts

It definitely could be a problem with improper bellows installation. They were not installed by a marine mechanic. My question would be , could my leak come from the bellows if I could get water to come in from the outlet hole. I had to agree that it seemed like a rusted out exhaust part. Come to think of it, when I apply the hose stream to the outlet hole, I hear it sound like it is filling something up before I see water come in. I have not been able to locate the exact location inside the engine bay due to the engine blocking my view.

I just went and bought a long 1/2 extension to give me some torque on the breaker bar. Wish me luck!