Which lower unit should I use? Fix bent skeg?

I'm putting together a 1973 Mercury 1500 for my boat. Right now it has a late 80s lower unit with a bent skeg. (from a Mariner) I have also come into possession of another LU, mid to late 70s. (I can post the serial number if it makes a difference) This LU has a straight skeg, but somebody has cut about an inch straight off the bottom.

Which lower unit should I use? I seem to remember something about the later models being a little different. (good or bad?) How would I go about straightening the skeg on the first LU? I'm afraid of just snapping it off. Does the missing area on the bottom of the other skeg have an effect?

I will post a pic of both units tomorrow...

Re: Which lower unit should I use? Fix bent skeg?

You have multiple choices to repair what you have. Look at these skeg in Boat Parts & Accessories For Your Boat - iboats

A welded replacement is best and provides the least drag....... a "complete" skeg will protect the prop.

Re: Which lower unit should I use? Fix bent skeg?

I don't think either one is so bad that I need a replacement skeg. The one that has been cut looks like it is still long enough to protect the prop:


Is the newer style lower better than the old one...or just looks different?


This one is not bent that bad either...just enough to bother me:

Re: Which lower unit should I use? Fix bent skeg?

Why not just straighten out the bent skeg?

Re: Which lower unit should I use? Fix bent skeg?

Yesterday said:

Why not just straighten out the bent skeg?

Click to expand...

Yes, the question is how...without snapping it off? I have to pull the lower to replace the water pump anyway, so it would be the same amount of work to put either one back on.

Is the water pump the same for both units?

Re: Which lower unit should I use? Fix bent skeg?

a 73 and a late 80's? Somehow I'd think not the same, but I'd await others' advise to be sure.

Aluminum will bend a fair ways before it will snap, though you have to take it slow and patiently. Some use heat but it seems to me that changes the equation considerable with aluminum. Something to do with the annealing process. Perhaps try youtubing 'bending aluminum".

Re: Which lower unit should I use? Fix bent skeg?

I "borrowed this idea from a posting elsewhere:
" trim your motor up all the way,put two 2x4's (one on each side of skeg)together w/c clamps and slowly move in the desired direction. "
Others speak of rubber mallet and a wood backing.
You can also cut it off leaving a 3" chunk and put a skeg guard on it. (As sold on Iboats)

All advise says "slow and steady". I've done some heavy aluminum bending and that's always worked for me, though I'd do it in the warmth of indoors, in fact I'm in the middle of doing my own including removing a twist in it.

bunch of posts on this forum to that effect as well:
Google

great thread from Iboats:
http://forums.iboats.com/boat-topic...opics/bent-skeg-how-bad-still-use-262619.html

Oh I also should add this:
Unless I'm mistaken, the gearing in those two lower units is different. If so the original era L/U might make a better marriage with your engine. Again perhaps someone else will chime in here?

Re: Which lower unit should I use? Fix bent skeg?

They made almost every year from 1969 to 1982 different but all fit the same motors. 70-71 used 1.78 gears. I used a 21" pitch 3 blade bronze with this ratio, but the 2:1s will give lots more torque. I'd use the newer one. Might have helical gears, less resistance and more contact. Look up in the parts listing for pics of the gears. If the skeg is as little bent as it looks Use two hammers, one with a plastic head. I'd heat it up with a propane torch for 5 or 10 min with the oil out. It shouldn't hurt the seal because it's all solid metal. Turn it upside down. Check my reply to help pick a prop today. It should be helpful. Let me know by reply or PM.

Re: Which lower unit should I use? Fix bent skeg?

A welded skeg works good sometimes. Sometimes they completely fall off when you bump into a rock. Sometimes they separate violently at high speed. Welded skeg lowers are not even allowed on the classified section at screamandflycom for good reason. Ive welded skegs and they turned out great then a few years later I looked down and they were gone. I surely wouldnt worry about an inch off the bottom of an otherwise good lower.

For my buck I'd straighten the late 80's skeg.

The late 80's inline swepped skeg will work fine and you can straighten them out just fine with a rubber mallet backed by a steel block . I wouldnt worry much about protecting the prop with the skeg. If you hit the skeg bad enough to damage the skeg you will surely damage the prop and shaft . Trust me on that one.