cracked foot !!! can it be fixed ???

heyitswebb

Seaman Apprentice
Joined
May 31, 2003
Messages
43
the left side of the foot on a mercury 800 80hp 1972 model has a crack in it the shape of a [c]. It is on the left side in the middle where the prop shaft runs. The crack was caused by water freezing over the winter. Can anything be done or will this require a lower unit replacement. If no fix can be made, what are my options on finding a lower unit to fit the motor. Keep in mind it is a 1972 merc 800 80hp. The crack is pretty bad, I know it will leak if oils is in. The side that the crack is on actually stick out about an 1/8 of an inch. Looks like it could be pushed back in place with ease. What to do, best advice is always appreciated . Thanks Tim
 

wayne h

Master Chief Petty Officer
Joined
Apr 29, 2003
Messages
862
Re: cracked foot !!! can it be fixed ???

look on ebay you might get lucky and you might be able to get it welded but i am not sure how bad it is.
 

Bearcamp

Petty Officer 1st Class
Joined
May 21, 2003
Messages
341
Re: cracked foot !!! can it be fixed ???

It's aluminum so it can be welded. Just make sure whoever does it, is good. You can get it too hot and will cause problems.
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: cracked foot !!! can it be fixed ???

If it's not load bearing, grind a "V" in the crack, use 80 grit and sand area all around the crack and patch it with JB Weld.<br /><br />c/6<br /><br />Hooty
 

heyitswebb

Seaman Apprentice
Joined
May 31, 2003
Messages
43
Re: cracked foot !!! can it be fixed ???

Thanks for the tips, but I don't know if it is load bearing, or what is on the inside of that part of the housing. Do I need to remove the prop shaft before it gets welded or before anything is done to fix it. What other damage might have been caused by the freezing water? I kind of want the worse case situation, I always love good knews, you know the kind you get when you take your boat to the shop. Thanks, keep coming with the comments. Tim
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: cracked foot !!! can it be fixed ???

You may not have to disassemble the gear case but you're gonna have to get all the lube out so's it doesn't burn up.<br /><br />c/6<br /><br />Hooty
 

heyitswebb

Seaman Apprentice
Joined
May 31, 2003
Messages
43
Re: cracked foot !!! can it be fixed ???

I have gotten a diagram of the lower gearcase of this 80 hp merc. I think I can disassable it ok but I would like to know if there is anything special I need to know before I start on it. Are there any hidden pieces or anything I need to replace while I have it all apart. Is there any special way to put it back together or any thing I need to do give it better protection? I'm ready to try it, just want a little more advice on it. Thank Tim
 

heyitswebb

Seaman Apprentice
Joined
May 31, 2003
Messages
43
Re: cracked foot !!! can it be fixed ???

I'm ready to pull apart the lower gearcase, Is ther any special advice you can give a first timer? Anything I need to replace or do while I have it apart? I have a diagram of the lower unit and it looks pretty simple, I just wanted a little more advice before trying to fix the crack. Thanks Tim
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: cracked foot !!! can it be fixed ???

I'd still try JB Weld first.<br /><br />c/6<br /><br />Hooty
 

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: cracked foot !!! can it be fixed ???

Hooty has given you the first thing to try. If that dosen't work you can always disassemble it. His solution requires little work, low risk and is cheap to do. Why go further unless you need too?
 

heyitswebb

Seaman Apprentice
Joined
May 31, 2003
Messages
43
Re: cracked foot !!! can it be fixed ???

OK, I have used the JB weld and it is holding ok. No leaks yet, have not water tested only to see if it will hold oil. So far so good. NOW I HAVE ANOTHER PROBLEM. The control box is in bad shape. The question I have on this is, Will just about any old mercury control/ shifter box work or dp I have to find one for that model and for that year motor. I have a control for a 1985 35hp mercury, but this is a 80 hp early 70's model Mercury, so what do you think, I value your opinion. Thanks Again, Tim
 

heyitswebb

Seaman Apprentice
Joined
May 31, 2003
Messages
43
Re: cracked foot !!! can it be fixed ???

I know this may sound stupid but will just about any merc. shifter / contol box fit on another merc. motor ?
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,757
Re: cracked foot !!! can it be fixed ???

Open them up, if similar, try the other one. What have you got to lose?
 

St. Bennett

Cadet
Joined
Jun 15, 2003
Messages
21
Re: cracked foot !!! can it be fixed ???

Look, JB weld will only cause you further problems down the line. After time it starts to break down and crack. I reccommend that you find a good TIG welder. It should cost no more than 50 bucks or so. That is the strongest weld for aluminum.
 
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