'72 100hp evinrude starting issue

[bald tom]

after 3 to 4 years on non use, I have decided to try to rescue this oldie but goodie. Originally, absolutely nothing was happening when I turned the key. I have worked my way through the starting system (including cleaning and reinstalling the starter motor. I can now get the starter to turn the engine over at a slow speed when the spark plugs are removed. However, with the plugs installed, it barely turns over. I have sprayed fogging oil in the cylendars to try to lubricate the walls, etc. Any suggestions for what to do next? I am thinking of putting some outboard oil (TCW3) in the cylenders. Is that a good idea? Should I try to use the starter for a minute or more (without plugs) to see if something loosens up? Also, what about trying to start with only 2 (of the 4) plugs? The idea is to let it run for a minute on the hose, then switch plugs repeat, then try 3 plugs, repeat, and then four. I know it will run rough with only two plugs, but isn't that better than not running at all?

Also, the lower unit oil has not been changed for about 10 yrs. I was going to change it after it was running. Should I change before it runs?

Thanks!!