Rotax 503 UL aircraft engine ,It is a provision 8 engine , 50 horsepower  , single carb ,  This engine was traded  into Airscrew Performance with a  failed Ducati ignition system  it has 266 hours on it since  brand new  and  replaced with a 582 UL engine ,  the ignition system was replaced with a brand new Nippon-Denso  DUEL ignition system   along  with a brand new crankshaft , pistons,  rings,  all gaskets, bearings  and seals  and test run on  an engine stand  ,   NOTE  the engine was damaged in shipping when brand new and the lower engine mount lugs were replaces and then  ran the 266 hours  until the Ducati ignition failure  ,Note because there are  three gearbox  assys  and four different  gear ratios  available   no gearbox reduction drive will be included in the listing , Note  , there are four different  exhaust/muffler systems available for this engine  no exhaust will be included in this listing , In other words what you see in the pictures is EXACTLY what you will receive if you are the lucky buyer , The buy it now price is $ 3200  which includes the free shipping to you ,SO  If I accept a lower offer from you then you will be paying the shipping of your choice , Thanks for looking