Tecumseh and Clinton seem the be similar in a few ways .. Is there and relationship between the 2?
Dug around on the internet, as this subject interests me too:
No relationship that I can see. Lauson's first small and portable, successful engine was the model VA in 1929. Clinton however didn't start producing engines until the mid forties. About 15 years after Lauson was an established company.
Briggs was the real grand daddy of the small portable engine.
I suspect there was a degree of good old fashioned industrial espionage going on, but no proof. I don't see any similarities between my US Marine Power 580, and my Clinton A400.
If you dig in to Clinton's history, it is quite sad, in that they sold the business to an investment firm who didn't really invest much in the company. Meanwhile, as we know, Tecumseh bought Lauson, and various sales and acquisitions from Chrysler, West Bend, Power Products, and US Marine Power, merging with Mercury Marine, etc. with their two strokes.