swapping lower units

[bkyser]

Here's a new question. I hope it's not too stupid...I have a 1970 80hp Merc. 4cyl outboard. I've been trying to troubleshoot the old "no spark" problem for a while. We have a local "Free Ad" paper, that has a few Mercs ranging from 85hp. to 115hp. that they say run well, but have bad lower units (still trying to find out years of these motors). How can I find out what lower units will work with what motors? I'm just wondering if this wouldn't be less expensive than trying to get my current electrical problems solved. <br /><br />Any help would be appreciated.

 

[cclemon]

Re: swapping lower units

Mech,<br /><br />That's not a stupid question, that's a smart question. I'll bet there are some guys out there that know which units will fit. You may be able to get an idea by checking a manual. You can refer to the "gear ratio" and "fluid capacity" in the lower unit section. It might help to eliminate the units that don't match.

 

[oldboat1]

Re: swapping lower units

I agree. That is one of the beauties of owning an outboard. An amateur with a little nerve and a little skill can do the kind of mixing and matching you are suggesting. Get clear about what model you have, and look for an identical one. Failing that, you might have to get into the nitty-gritty of what works with what, but try for an exact match first.

 

[harrison20002]

Re: swapping lower units

Mechanically Challenged, One critical point in L/U exchange is the shifting rod length. If all else works and you have enough rod to adjust it should work. Stuip question? No, a stupid question is when someone asks a question and when he gets the answer, wants to argue about it. Happy Boating, Hal