Re: how the heck do i get this off
Its pretty simple, put it forward, unbolt the trim cylinders and remove six nuts.
You do want the manual though, it will show you how to align the motor. You will need an alignment tool also.
The GM 250 I6 is a great engine. It makes good torque and its very smooth. My father loves those little engines and has several of them in different cars and trucks (and the garage floor).
What kind of work are you doing to the boat?
As Frosty mentioned, the wiring does look like it needs some attenntion.