Ian wrote:

The Tecumseh 4 stroke engine on my (old) Ariens snow blower has
progressively required more choke to keep running. At the start of the
season I'd start it with full choke and eventually move it to "no
choke". Recently it has needed full choke just to run, even when
warmed up. Now it stalls if I don't keep priming it ("Mega Choke").

Any suggestions on why this would happen and is there an easy DIY
remedy?

Sounds like an air leak somewhere...look for loose connection of carb,
etc.