The McCulloch MAC-101, also called the MC-101 and MC101, is a two-stroke, single cylinder engine that was designed and produced by McCulloch Motors Corporation for kart racing use, being introduced in 1967. It was also used in the late 1970s and early 1980s as an ultralight aircraft engine.
All models in the MC-101 series have a bore of , a stroke of and a displacement of .