I have seen some guys convert some 4 stroke weedeater engines over to RC model airplane engines. But these engines are much more lightweight and have a special walbro like carb on them already. But because of rhe oil sump, some aerobatic maneuvers have to be avoided.

Usually the utility engines vibrate a lot, so you need to use a vibration isolation motor mount. Then the engines are very heavy so you need to figure out a way to reduce the weight. next the oil sump can be a problem, so you can't fly certain aerobatics then. if the carb is a flat carb you have problems too. So you would need a 4 stroke walbro carb for the engine. Then the engines are designed to run slow around 3.600 rpms so they may not make enough power to fly a plane, hard to say. But at 3,600 RPMs they would sound more realistic though.

Has anyone made 4 stroke chainsaw engines or maybe 4 stroke leaf blowers yet?