Four stroke engines tickle the fancy of many of us because they are simply “neat.” Their sound stirs the imagination, and they carry the airplane around the sky in a more realistic fashon. But they are expensive. A lot of money can be saved by buying used RC engines, if you can find a dependable used engine. I try to make all of my used engines relaible through repair, testing, and rating so you will know what you are getting before you buy.