Tecumseh Products, the parent company is long gone from Tecumseh, Michigan. The plant is now a Brownfield redevelopment. All that's left is an R&D center near Ann Arbor and a large empty building in Tecumseh that no one wants. I know many people around here that worked and retired from the 'Products' as it's referred to. Most lost their pensions when the company folded. The owners of the Products got greedy and started selling off divisions and divesting the company and along the way, screwed the employees. It was a good job for the folks around here, who farmed as well. Back in the day, the Products would allow their employees time off for planting and harvest.
Tecumseh Products prime product was refrigeration compressors. The engine division was an acquired company.
Interestingly, I still own an Ariens Rocket, rear tine tiller with an HH Tecumseh engine and a Troy-Bilt with a Tecumseh and both run well but both burn oil, a trait of Tecumseh engines. I just add oil and run 'em.
Not bad motors, just weak oil control rings. The HH on the Ariens had to be replaced early in it's life. One of the screws that secured the butterfly throttle plate came loose and got in the combustion chamber and went through the piston. Excellent quality control....

Now I have a long block with a holed piston on the shelf. I'll sell it someday. I hear the HH engines are no longer available. Someone out there will need one, sometime....
My favorite engine is a Kohler domestic K series thumper with compression release. Nothing beats the sound of a Kohler at idle.