Mariner Lower Unit Removal Help!

[minuteman62-64]

Finally at the point where I'm going to have to drop the lower unit on my 1982 30 HP Mariner to see why its not pumping water. After reading a number of posts I got the impression that it's a piece of cake. Naturally I run into a problem right out of the chute.

I have the factory service manual, so I'm walking through the steps as perscribed:

Remove Propeller 7 reverse thrust hub - check.

Shift mtor into neutral and tilt motor up - check

Disconnect lower shift shaft by loosening the jam nut and unscrewing connector - arrrg!

The jam nut loosened easily. However, when I attempted to unscrew the connector, no dice. The connector moves easily about 1/16 turn both clockwise and counter-clockwise. From the manual it looks like the the connector detaches from the upper shift shaft by unscrewing from it (which would appear to be a counter-clockwise rotation). However, when I attempt either a clockwise or counter-clockwise rotation, after that first 1/16 rotation it won't budge. If I apply some force the upper shift shaft begins to torque.

I'm afraid to apply too much force for fear of creating more problems than I already have (like shearing the upper shift shaft because of excessive torque).

Any advice/assistance appreciated. What am I missing?

 

[minuteman62-64]

Re: Mariner Lower Unit Removal Help!

Update. Fortunately I decided to take a nap before breaking out the sledge hammer and sawzall. In a more peaceful frame of mind I took a closer look. By working the shift lever back and forth I was able to see that the connector I was trying to loosen is, in fact, a plain old coupling nut. It just seems to be frozen to the upper shift shaft. What I was thinking was a 1/16 turn of rotation was just the rotational slop in the upper shift shaft.

So, my task is to free the coupling nut from the upper shift shaft. It takes a 10 mm wrench (mine is only about 4 inches long) so the torque I can apply is limited - unless I slip a length of pipe over the end of the wrench. However, I'm worried about over torqueing and shearing the upper shift shaft or damaging the connection to the shift handle. I squirted some liquid wrench on it and will try again tomorrow.

Any idea how much torque I can apply w/o damaging the upper shift shaft and associated parts?

Is there an easy way to disconnect the upper end of the upper shift shaft and bring both the upper and lower shift shafts down with the lower unit?

Apply heat to the coupling nut or freeze spray to the shift shaft? Not sure of a good heat source - I don't want to damage the aluminum components.

This, of course, begs a question. In April I had a guy replace (allegedly?) the water pump impeller. The motor only has about 2 hours on it since - about a half hour of that in my yard, on the muffs. So how did the mechanic drop the lower unit? Or did he?