Crack in the bottom end (skeg) of 1976 Johnson 40hp

kcwright

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OK, here is my issue. I bought this boat (almost free) but there is a crack in the bottom end (images attached). 1st question, can I use JB Weld? 2nd question, there seems to be 2 drain plugs can I cover the side on as I think the crack goes past the hole?
Looking for a cheep fix as I have very little in the boat.
Thanks for any help.
Kevin
40a.jpg40b.jpg
 

Chinewalker

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

That side "drain" that the crack goes through is actually the hole for the shift fork pin. It MUST be there! You may have an issue realigning the screw in the hole as the shift fork inside the gearcase has a habit of falling out of alignment when you remove that screw. You might get by with realigning it with a pick or an awl.

As for dealing with the crack - going through the hole like that makes for a dicey issue, as the hole itself is likely out of round and unlikely to hold the screw tight for long. I would also be concerned with WHY it cracked. Most likely due to water in the gearcase, which means you may have rusted gears, bearings, etc. I'd tear it down, which would also enable you to take the skeg to a welder to have him sew it back up for you. Leaving a long steel bolt in the threads may keep the weld from getting into the threads, and then you can use some thread locker to help hold the screw/pin in place when you're done.
 

kcwright

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

Thanks for the quick response!
OK so can I tear it down from the 9 screws you see in the image? Or do I have to go higher? That pin will go back in, should I put it back in while I still can?
Again thanks for the help and being patent.
Kevin
 

Chinewalker

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

Yep, 9-screws and the skeg half comes right off. Leave the pivot screw out for now - it has to be out to remove the skeg anyway...
 

kcwright

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

You're a good man sir. If / when I get stuck I'll be sure to bother you again...
Thanks
Kevin
 

kcwright

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

I'm back! With more images and a bit of good news for me. Looks like the cracks don't go to the pin hole and no rust or filings to be found.
Did find fishing line around the shaft and a bad seal.
Any idea on a rough cost of having something like this welded? We talking $50 or $200?
40e.jpg40c.jpg40d.jpg
 

nwcove

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

what part of the world are you in? just asking as that looks like a "freeze" crack, and in pic #2, there appears to be another crack under the the first one. jmo, but it may be a better option to look for the bottom section of the gear case from a salvage yard/fleabay etc.
 

kcwright

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

Ontario, little west of you. Ya I would guess ice as well. Just looking for a cheep fix.
I'll look there as well, is there a lists out there of compatible years?
 

boobie

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

You can't use the bottom half off of another g/c as they are line bored at the factory when manufactured as a complete housing.
 

Chinewalker

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

You can't use the bottom half off of another g/c as they are line bored at the factory when manufactured as a complete housing.

Yes, and no. It is actually relatively common practice to swap skegs around when needed. These old OMC split gearcases are very forgiving and the tolerances are usually close enough to allow a skeg replacement.
 

Chinewalker

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8,902
Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

You can't use the bottom half off of another g/c as they are line bored at the factory when manufactured as a complete housing.

Yes, and no. It is actually relatively common practice to swap skegs around when needed. These old OMC split gearcases are very forgiving and the tolerances are usually close enough to allow a skeg replacement.
 

D.spencer

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Re: Crack in the bottom end (skeg) of 1976 Johnson 40hp

If it were mine, I would drill the ends of the cracks so they do not go any further, use a low temp aluminum rod like the kind designed for a propane or oxy/acytlene torch( practice on some scrap before you attempt this) and finish it off with loc-tite anerobic sealer to make shure everything is sealed. To make sure it is sealed, I would use a shop vac and seal the hose to the inside of the cavity via a piece of plywood bolted to it-bolt the piece to the plywood, drill hole for vac hose, seal hose to wood and seal edges and ends with clay. Pull a vacuum on the inside and apply the loc-tite to the outside, it will creep into any pores and stay there. The vac is only necc to get the material pulled into the piece, it is not needed after that, let it dry thoroughly before re-assembly. Tig welding this can be done but may be fret with oil trying to come to the surface contaminating the weld. It might be possible to do this repair without welding at all and just do the loc-tite procedure described above. My 2 cents-Fwiw.
 
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