In the early 1900's, the Johnson brothers from Terre Haute Indiana made an inboard boat engine, dabbled in aviation - actually making the first monoplane flight in 1911, and made motorcycle engines well before settling in to manufacturing outboard engines.
Because of this, their company had monikers such as the "Johnson School of Aviation", and the "Johnson Motor Wheel Company". When the motorcycle boom went bust with the advent of the Ford Model T around 1920, the brothers needed a market for their small motorcycle engines.
In 1921, the Johnson Outboard Motor Company was born when they converted their small engine design to be water cooled and to drive a propeller shaft. Their model "A" sold well and became affectionately known as "Waterbugs".
Millions of Johnson motors have been made since, and the company pioneered many features that are found on all outboard engines today.
I have several Johnson Outboard engines in the collection, and here's photos of some of them!