Apparantly, the previous owner could not get it to seal, or for whatever other reason, decided to glue the drain plug shut.
Some people should never be allowed to own anything mechanical.
Not that I could tell it was glued from the outside... I even went out and bought the proper sized screwdriver beforehand, but I just ended up stripping the slot. Not that I've ever done *that* before. If I had an impact bit for my air tool, things might have turned out different.
Go to Sears and buy a hand impact tool. Under $30. You hit the tool with a hammer and the downward force is translated into a twisting motion at the same time. It keeps the bit firmly in the slot and turns the screw. No more stripped screw heads.
But I ended up using a screw extractor to get it out, and then running a tap through it to try to clean out the hole. The threads were too much of a mess. It looks like I will be drilling the drain hole oversize.
Buy a heli-coil kit of the size the present screw is, tap the threads with the included tap, coat the heli-coils' outside threads with LocTite Yellow and insert the heli-coil into the new threads you just tapped... let dry.. jobs done. Put the new screw in after it's dry and move on to the next job.
I was planning on removing the lower unit anyway to get at the water pump and to clean the housing up. The housing has got some pitting where the paint flaked off.
Given the length of time the boats been sitting, changing the water pump impeller is a smart move. You might want to consider sandblasting the outside of the lower housing, priming and painting it with an epoxy paint. Nothing like epoxy paint to stop corrosion in it's tracks
No more boat work until the shed is done...
Ummmmmm...ya..
BTW, can you buy just a lower unit gearcase housing for an old engine (1986)? This is more of a curiosity question, since a new housing is probably more expensive than a decent used lower unit.
If you look long and hard enough you can find anything on the internet.