The modern two-stroke, high speed, high power outboard marine engine was pioneered in the period 1940-1967 by E. C. Kiekhaefer and his engineers at what is now the Mercury Outboard Division of Brunswick Corporation.

extract from patent showing motor

Swing-up action protected both boat and motor, while the power lift protected its owner.

Kiekhaefer foresaw that the boating public would be interested in larger and faster boats of modest cost and light weight to permit transportation by private road vehicle. To provide the necessary power plants required the satisfaction of the following technical requirements:

  • High power-to-weight ratio,
  • Reliable steering.
  • Resistance to collision with floating or submerged objects.
  • Reliable operation with ordinary fuels.
  • Acceptable noise levels.
  • Good overall efficiency.

These requirements called for a large number of innovations that were first incorporated in Mercury motors, and eventually widely adopted world-wide by the outboard motor industry. Together with the molded glass-fiber-reinforced hull, the modern high performance outboard motor has made pleasure boating accessible to people whose dwellings are remote from boating waters, but within driving distance. Performance and load capacity are available to the person of moderate means in the modern trailerable boat that was not even to be had by the very wealthy thirty years ago.

Among the major innovations and some of their primary contributors are:

High Power-to-Weight Ratio
C.D. Strang, L,P, Post, R.T. Johnson, R.J. Shanahan
1950 Inline, alternate firing 4 cylinder two-stroke engine
1956 Inline, alternate firing 6 cylinder two-stroke engine
Reliable Steering
1956 - E.C. Kiekhaefer, L.P. Post, W.E. Witte
Push-pull cable steering
Impact Resistance
1951 -C.D. Strang, L.P. Post
Rubber cushioned hub propeller

1958 - E,C. Kiekhaefer, C.F. Alexander
Hydraulic shock absorbers on tilt-motion 1958
Patent awarded 1960 (pdf)
Patent which incorporates power lift 1961 (pdf)
Noise Reduction
1957 - C.F, Alexander, D,F.McCormick, W.E. Witte
Exhaust port passes through the propeller hub
Improved Engine Efficiency
1959 - C. F. Alexander
Sequenced spark advance and throttle opening; Advancing spark before opening throttle greatly improved lower mid—range fuel economy.
High Propulsion Efficiency
1966 - E.C. Kiekhaefer, I.W. North, D.F. McCormick
Power trim; allows operator to adjust thrust axis while underway and so trim boat for minimum drag.
Fuel Tolerance
1966  - F. Minks
Capacitor-discharge ignition, which nearly eliminated fouling of spark plugs and preignition

Next - Bruno Nordberg generates a lot of power.