Welding/repairing damaged skeg

syzygyus · Apr 27, 2013

I have a question about welding a damaged skeg (see attached damage).
Can this be done without disassembling the guts of the lower unit? (And if I need to disassemble, any hints/suggestions? Is it involved?)

I'm not exactly sure of model of drive unit. It's from a 1985 Four Winns, with 170HP 3.7L 4cyl Mercruiser IO. Drive unit labeling is worn, so I'm not sure of model. Merc Alpha (X)? or Bravo?

Thanks.

crabby captain john · Apr 27, 2013

Re: Welding/repairing damaged skeg

It looks like there is enough to weld to but it is easier to attach another over what is left. Keelguard and others make them. I'd prefer that to adding all that heat.

glenn property of pam · Apr 27, 2013

Re: Welding/repairing damaged skeg

alluminum clean is a pain to weld add all the contaminates and thats means more heat which travels so i would avoid welding it as a skeg guard is cheaper than welding and a seal kit

syzygyus · Apr 27, 2013

Re: Welding/repairing damaged skeg

crabby captain john said:
It looks like there is enough to weld to but it is easier to attach another over what is left. Keelguard and others make them. I'd prefer that to adding all that heat.

I think too much was broken off for a keelguard. I was going to have someone in my shop weld an additional piece of aluminum (or so I planned). I'm going to investigate local prop shops too.

PS for identification, only thing I can read on the out drive is a big "4" and Manual says Model 170MR. So Is a R, MR, Alpha I synonymous? (checked http://forums.iboats.com/mercruiser-i-o-inboard-engines-outdrives/how-identify-alpha-style-outdrives-592828.html link for identifcation)

pevaguy · Apr 27, 2013

Re: Welding/repairing damaged skeg

I have welded a skeg on in the past. The way I have done it is to first cut and grind the damaged skeg and the repair part so that they fit right and you have clean metal to weld to. Before welding wrap the gear case with water soaked rags to protect it from heat. If it starts getting too hot, take a break and re-wet the rags as needed to control heat.

LippCJ7 · Apr 27, 2013

Re: Welding/repairing damaged skeg

pevaguy said:
I have welded a skeg on in the past. The way I have done it is to first cut and grind the damaged skeg and the repair part so that they fit right and you have clean metal to weld to. Before welding wrap the gear case with water soaked rags to protect it from heat. If it starts getting too hot, take a break and re-wet the rags as needed to control heat.

Outstanding description, I can't add anything except that you don't have to remove the "Guts" the wet rags should do plenty to draw heat from the weld and insure your internals will be fine provided you don't dink around with your weld, do a good job but do it quickly.

pevaguy · Apr 27, 2013

Re: Welding/repairing damaged skeg

Lipe' Yes you are right, by controlling the heat, there is no need to disassemble the lower unit. Also, I prefer TIG welding over MIG. TIG is much more controllable and precise.

Frank Acampora · Apr 27, 2013

Re: Welding/repairing damaged skeg

However, do drain the oil first. The heat of welding can expand it enough to possibly damage a seal.

pevaguy · Apr 27, 2013

Re: Welding/repairing damaged skeg

Frank Acampora said:
However, do drain the oil first. The heat of welding can expand it enough to possibly damage a seal.

I'm thinking that the oil passage way between the lower section and the upper (removed) section is open so any expansion would be relieved with no harm to the seal. I maybe mistaken, it wouldn't be the first time.

four winns 214 · Apr 28, 2013

Re: Welding/repairing damaged skeg

Good prop shop can weld a new skeg on there and make it just like new.

5150abf · Apr 28, 2013

Re: Welding/repairing damaged skeg

Mine was worse than that and I welded it, drain most of the oil and put wet rags on it and keep checking the rags.

I clamped a small steel plate to the skeg as a backer and laid a weld the shape of the skeg and just started filling till I got to the lower, this way the heat isn't on it till the very end and one side at least is really smooth.

I would do it all with weld rod, it will be a lot more durable, if you just weld a piece on it will snap off in the same place next time you hit and the key to welding cast is super low heat.

I use a miller 250 and run about 85-90, I have found more heat causes a lot of porosity, I do all my own props and the skeg once in a great while.

Feel free to PM me with any questions, and so you don't think I am talking out of my backside I have been welding aluminum for 26 years.

gm280 · Apr 28, 2013

Re: Welding/repairing damaged skeg

syzygyus said:
I have a question about welding a damaged skeg (see attached damage).
Can this be done without disassembling the guts of the lower unit? (And if I need to disassemble, any hints/suggestions? Is it involved?)

View attachment 191197

I'm not exactly sure of model of drive unit. It's from a 1985 Four Winns, with 170HP 3.7L 4cyl Mercruiser IO. Drive unit labeling is worn, so I'm not sure of model. Merc Alpha (X)? or Bravo?

Thanks.

I have read yours and all the other comments on this issue. And I agree with everybody except one issue. I would most certainly disassembly the lower foot completely. WHY? Because you are welding on the lower foot to replace a broken off skeg. I would also rebuild the foot at the same time therefore making sure that everything inside was working properly too. It would be a great time to inspect and/or replace any bearings, bushings, "O" rings, seals, gaskets and of course the water impellor too while you are this far into this project... The heat, even low amounts of welding heat (which still is extremely hot), can melt seals, ?O? rings and the possibility of warping parts... You would surely kick yourself to go through all this and then after putting in back on the engine find out it is leaking or other problems. JMHO!

Don S · Apr 28, 2013

Re: Welding/repairing damaged skeg

If you would rather not weld at all, there is another alternative.
SkegGard with Skid Plate 99002 - Skeggard - iboats

iboats625 · Jun 3, 2013

DIY Skeg replacement

DIY Skeg replacement

I have an older Evinrude 70 hp outboard motor with most of the skeg gone. I went to Cabela's and looked at the replacement units. They cost around $100. I think I can make a replacement similar to the one I saw at Cabela's from some 3/16" aluminium that I have. This is not welded to the skeg but fits over it and secured by 2 bolts. I have researched doing this on the internet but did not find any comments about trying this. What are the cons about this DIY fix? I think I know the pros.

Chris1956 · Jun 3, 2013

Re: Welding/repairing damaged skeg

Some years ago I broke the skeg off my Merc IL6. Merc provided a replacement skeg and the welding shop did the rest. I didn't drain or disassemble anything. The shop was a pretty good one, with experience welding skegs.

Welding/repairing damaged skeg

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