Harry,
Yes, the recoil start models (standard on the Original, 70, 71, 72, electric start was optional) had a off/on key switch. It was a different switch than what was used on the electric start versions. In the on position the switch was open allowing the magneto to function, in the off position the switch was grounded, to kill the mag. Model 73 was the only 7 hp model with electric start as standard, and the recoil start was not available.