I considered plonking my ASP 52 4-stroke in mine to see how it goes, but the throttle lever is tucked right in behind the cylinder so it'd be a bit of a pain to re-configure the throttle linkage.
On the FS70, the throttle lever sticks out to the side, so all I had to do was to use a new pushrod bent to loop back to the lever. Works fine....

BTW The ASP 52 only cost $99 off of eb%y, I don't know if the same guy still sells 'em....