Finally got around my old machine. The Tecumseh s/n is HM80 155 128H SER 2307D. The 924050 was produced from 1980 to 1991. My s/n gives me a manual printed in 1983 on Operator's Manuals - Ariens. Hence my machine is from 1983-1991. As the bulild date of the engine is 2307, «october year 2», this engine must have been produced in 1982, and fitted on an Ariens later than this. Therfore, my machine is from the year 1983 ❤ 39 years old this year!