Do the make a 4 stroke inbord nitro? Was just wondering. thanks
Shawn

O.S. used to a few years back but you don't see them around much.

I happened to have out my old OS engine charts (80's vintage) looking up something. They show the following 4 stroke marine engines: FS-40-M, FS-60-M, and FS-61-M.

Just like a 4-stroke in a heli, you would need to gear it up and/or turn a larger prop to get a 4-stroke to be any good. Even then a good 2-stroke will put out more power at a smaller displacement.

This is also true in Motocross, where 500cc 4-strokes compete with 250cc 2-strokes on the same level.

Thanks guys. I wasn't looking for speed records. I'm going to build a rescue/suport boat and want to have some low end power and reliable idle for it. I'd like to find a jet unit to put on it with a reverse bucket. That FS-61-M would do the trick.
Thanks again
Shawn

And you get cool sounds, a small pipe and can turn a big prop at low speeds (to avoid huge rooster tails from a scale ship). Yeah, a 4-stroke should work for that.

The challenge will be finding one...