From 1931 on, the A class engine was alternate-firing. The Evinrude 460 F class engine was a four-cylinder beast. When Mercury engines arrived on the outboard scene in the late '40s, they simplified the mechanical side of racing. In the interim 50 years, relatively few changes have been made to engines used in stock classes. Most of the refinements have been in elements such as electronic ignition and improved carburetion.
Drivers still start their engines with a rope and still have to service lower units.
One of the major political developments in the Stock category came in the late '70s when the Japanese-made Yamato was approved for the 20SS class. In the early '80s, another Yamato model became the only approved engine for the popular C Stock class, replacing the aging Mercury Mark 30H. Yamato engines, made for Japan's pari-mutuel outboard circuit, are reconditioned and sold to U.S. racers. Among PRO classes, which clung to the Evinrude, Johnson, and Elto engines for a decade after Mercury solidified its hold on Stock racing, the end came swiftly. In the early '60s, Crescents and Anzanis ran circles around the traditional engines. A few years later, German-made Konigs were setting records the world over.