1969 Evinrude 55hp Hydro Electric Shift problem

Hi guys,

I have recently inherited a gem of a boat my grandfather had custom built back in 69 with a Evinrude 55hp Hydro Shift - 55973A. The boats been standing for a few years and I'm in the process of giving it a service but I've come up against a mystery problem.
I'm trying to remove the lower unit, I've removed all 6 bolts and I've disconnected the electric shift wires and tied some string around them so I can pull them back up, but for the life of me I can't get the lower unit off!! Is there something I'm missing or something I haven't done correctly? Any help or info would be much appreciated.

Thanks

Slim

Hopefully the drive shaft splines were greased. It may need a little GENTLE persuasion.
6 bolts looks right according to the dwg. None hidden under the trim tab, or the trim tab itself?
Hopefully the experts will be by soon.
Got any pics of that boat?

I have a bolt under the trim tab on my 1971 Johnson 50HP. Check yours to.
Bill