Replacing 1996 Yamaha 85 Trim Motor

[tryinthelake]

First post here. Any help to a neophyte mechanic will be greatly appreciated. Trim motor is rusted thru on a 1996 Yamaha 85. Getting a new trim motor tomorrow. Any suggestions or advice on replacing the motor? Trying to avoid taking the engine off but looks as though that is the only way. Still trying to get that back bolt off though.

Desperate to get it back on the water. Field testing some new saltwater baits and can't afford to put her in the shop for three to four weeks. Please have some compassion for a mechanical idiot who needs his boat running.

Thanks in advance from Lake Pontchartrain.