The first thing you need to do is mark a centerline on the transom. This seems like it should be easy, and while not too terribly difficult, there aren't really any completely straight lines to take your measurements off off. On top of that it seems nothing is mounted truely centered. Being the retentive type that I am sometimes, I ended up finding the center of the transom opening, the center of the metal piece at the back of the transom opening, the center point between the two rudders, the center point across the entire stern, the point that lined up best from bow to stern across the daggerboard (which was a pointless exercise seeing as the daggerboard can shift about a half inch in each direction) eventually I averaged that all out and finally just said this is good enough.
Next you use a template from Mercury designed make it idiot proof for drilling your mounting holes. The only difficult part? Driving around town for 2 hours until you find the one shop that stocks a 17/32" bit.
Once you've got that you done you've got this engine in a crate to deal with:
Now I suppose if you were a real manly man, with real manly friends you might be able to somehow lift this thing onto your boat. Seeing as it was just myself, I went with technology and choose to use an engine hoist...I don't recommend you try it any other way. I used the hoist to first lift the entire engine while still mounted to the metal crate. This seemd a lot easier than trying to lift it off the crate from a horizontal position.
Once you have it upright you can then remove the crate from around it.
Now it's simply a matter of pushing the hoist over to where you already have the boat prepped for the engine.
After that it's just a matter of four bolts, some nuts and washers and making sure you get it sealed up so it doesn't leak.
Based on the advise of some people on this board I mounted the engine using the top most mounting hole. This places the engine about 1/4" below the lowest point that they want it mounted, but it does allow you to tilt it all the way up with the seat lowered.
Mine still scrapes just a tiny bit and so there are some scuff marks on the engine from where it hits. The trade off is a couple hundred RPM in performance according to the shop I took it into after doing this install. Seeing as this is a Sailboat, it seems worth it to me to be able to get the motor out of the water to get as much sailing performance as I can out of the boat.
