Marine: Boating, Sailing, PWC, GPS and Navigation - OMC Tilt/Trim Motor Replacement Troubles

I have a 1990 OMC 140HP outboard motor used in saltwater. I'm trying to replace the Tilt/Trim motor which is badly rusted. I tried to push out the ss cylinder pin that connects the hydraulic piston to the motor bracket with a brass drift pin but I could move it only about 3/8's of an inch and therefore I cannot remove the entire assembly from between the motor brackets. This is necessary to get at the two back Phillips screws of the electric motor in order to remove it. I have soaked everything with PB Blaster for days and I tried heating with a torch. Since I couldn't remove the pin, I tried lifting the motor off the transom in order to get at the phillips screws from behind but found that the ss screws are still unaccessable due to no overhead clearance. I tried an angle phillips screw driver but can't get enough downward pressure to break them loose. I also tried a needle nose vise grip but there is not enough room around the heads to get a good grip. I then tried turning the screw heads with a small chisle, impacting the screw heads along the outer edge in a counter clockwise direction. Nothing is working. Please help. :( :wall: