The first seals used by Evinrude were cork. These were later "improved" by impregnating them with Graphite. During World War two rubber supplies were greatly restricted. In order to keep demand for rubber tires down, gasoline was rationed. It was during this time that our rubber tire dock bumpers disappeared, and my tire swing was stolen. The government poured a lot of money into research for rubber substitutes. Meanwhile Chicago Rawhide supplied seals for critical applications. So the first synthetic rubber oil seals appeared in 1946 on Evinrudes Weedless drive. By 1951 they were on the full line. . . 😀
