Thank you for your response.

I understand the problem / concern about cooling the engines (it is my biggest worry) but I have done a lot of searching, reading, e-mailing, etc. and have ran into many people that have taken non water cooled nitro engines and made "cooling coils" out of copper tubing. Where they take small copper tubing and tightly wrap it from the cylinder base all the way up to the head, the cool water is either forced (suction from driving the boat across the water) or pumped (with an electric water pump) thru the tubing and "spit" back into the lake after it has cycled around the engine. This method has worked very well in each situation I have come along in my research. Obviously none have used this exact engine (or I wouldn't be here asking all these questions) So lets say IF I have the cooling situation under control??? I'm just trying to plan for any other "major" hurdles.

I also know that I have to make a custom belt start flywheel (obviously since I won't be running an airplane prop) I have a lathe and machinging skills (so I would pretty much copy / compare a similar sized marine flywheel and would adapt it to fit the YS)

Attached are a couple "in progress" shots of my boat (just so you don't think this is all a pipe dream)