Fuel engines normally need some extra cooling when used in cars and boats. In cars they also need a dust filter on the air inlet.
1982: Racing on Schiphol parking lot. Stock-car racing with 3.5cc
1980: My own design power boat: Solid balsa sides and a bent board in
between. 3.5cc water-cooled engine
Used to start with a rope, but electric starter is much easier. Goes very
fast, due to big bottom surface.
1982: All-balsa model with deep V bottom. Powered by Mabushi-500 and 12V/3Ah
batteries.
1983: Propeller powered snow and ice vehicle. 1.5cc, clocked 52km/h on the
ice.