the sh company makes great engines, its not the vx that comes with them, its a different engine. Check your tank and make sure that its not clogged behind the nipple and fuel is flowing freely, thats the only reason why i can think that the engine would have been killed in 3 tanks. If its got a clean and oiled air filter, free flowing fuel and set rich enough, the engine should work great. All my stock redcat engines are working to this day.