Some company documents refer to the Mark 20 as a Rocket Deluxe, a designation mysteriously applied to 3 concurrent models in the years 1953-55. Some company documents refer to the Mark 15 as a Rocket Deluxe, a designation mysteriously applied to 3 concurrent models in the years 1953-55. MercElectric motors were electric start, with an under-flywheel alternator. The Merc 250 had modified intake ports.
All models are electric start.
Everything 1960 and before has Direct Reverse. The bankrupt Thor outboard company was acquired by the Kiekhaefer family in 1939. Carl Kiekhaefer changed his product's name to Mercury in 1940, and by 1947 his outboards had undergone such extensive improvement that they resembled their Thor-based progenitors in perhaps just a few specifications. The Lightning displaced 19.8 c.i., about the same as competitors' 14 HP motors, but it could put out over 16 HP on the dynomometer. He said it gave them more for their money.