Here's the situation:

I have a 1990 Champion 184 with a 1990 Johnson GT-150 on a 5.5" jackplate. After taking it on the river, I noticed that the motor moved about an inch when I stepped on the gas. At this point, I became concerned.

I removed the metal piece that goes across the top of the transom. The wood below this piece is rotted. Obviously, a transom repair is required. I have looked over a lot of the transom repair threads and think I understand the general process (remove old wood, rebuild, and re-seal).

Question #1: How do I access the wood to remove it? Can I cut off the section of top cap that is just above the transom and then re-glass it? How difficult would it be to re-glass the top cap?

Question #2: What materials would you recommend for this job? Is seacast acceptable, or should I track down some marine grade plywood? How much seacast would be required?

Question #3: Would it be acceptable to leave portions of transom wood that are not rotted? I ask because it appears the wood in the bottom half of the transom is solid (I drilled two holes last week to install a transducer...wood shavings looked fresh).

Thanks in advance. After re-doing all the electronics on the boat, pulling the gas tank to repair wiring issues with each of the pumps, painting the outboard, and wet-sanding the hull, I have too much time and money invested to give up now