well a 2 stroke with a diaphram carb. can be mounted upside down, right side up. or spun around in any direction while running if you would want. the carb works off of crank pulses which means that you do not need the fuel tank to be pressurized (glow engines)or gravity fed (4-stroke lawn mowers with a bowl carb). so for this reason a weed wacker engine is good for our radio hobby. just use a resistor plug to reduce engine noise.