From Longman Dictionary of Contemporary Englishoutboard motorout‧board mo‧tor /ˌaʊtbɔːd ˈməʊtə $ -bɔːrd ˈmoʊtər/ noun [countable] 
TTWa motor attached to the back end of a small boat
TTWa motor attached to the back end of a small boatExamples from the Corpus
outboard motor• He has asked us to buy him an outboard motor instead of giving cash.• All he needs is an outboard motor to go with it.• The two of us, maybe some others, are going to hire a boat with an outboard motor and perch rods.• It was cleaned, its seats and cockpit replaced, and a steering wheel, controls and outboard motor installed.• The answer is an electric outboard motor.• Foot steering of the outboard motor means that military users can keep both hands free to use weapons.• Went outside this morning and saw Noel pissing on the outboard motor. 