I don't really have any experience with older Tecumsehs, it's the newer ones (made a decade or less before bankruptcy) that worry me. I run synthetic oil, and it gets changed once a year, whether it needs it or not. We are not in a super heavy snow belt. This is somewhat unusual. I'll bet that machine gets 10 hours a year, at most. I don't know that it will outlive me, but it might come close.
I take the opposite approach to off season storage--I start adding fuel stabilizer to my 5 gallon gas can toward the end of the season, and fill everything full. If I get around to it, I will try to exercise dormant machines several times during the off season. And if that doesn't work, I got a 14 year old kid who is willing to take that stuff apart at the drop of a hat, and fix it. I haven't had one not start in more than a decade. Also, I never run ethanol in my small engines. I still have that option around here.
My furnace inlet/exhaust is not as low as you think it is. We just have that much snow! 😆