ABC engine sucked competely!! no offense but i had one of tower hobbies abc .46 engine, and i bolted it on tower hobbies fun 51. At first, it run just fine but more and more i pushed the aircraft to the limit such as hard snap rolls and aerobatics moves with heavy G pulls. the engine seem to hate me more every time I put it in the air. Just before i crashed on take off, the engine had to be on wide open trottle for whole time so it won't quit but every time, i land the engine quits and deadstick everytime. so i decide to dump the engine and replace with .50 ringed SX O.S. engine. I love that engine.