^^what he said about the serial number.
Anytime you talk Merc parts, it's easier if you have your serial.
The kits (if available as kits) aren't cheap.
It's a big job but it's all nuts-and-bolts stuff. I did a 25 a couple months ago and I think it was about three hours.
If it were my own motor, I'd have to think long and hard about converting mine vs selling it and buying what I need.
Your version is what everyone wants so it should be easy to sell - even more so if you have the controls for it.
If a guy's been trying to sell his tiller model for a while, you could probably get it for a song.
EDIT: need your serial, but one of the kits is p/n 816366a52 and retails for $1500 CAD.