Earlier here I mentioned I'd only used Seafoam in a trimmer without success.
I may run some through the old 'Moline. 231 cu. in., 4 cylinder gas engine. About 30 hp.
It has some symptoms that I suspect could be from ethanol gas. Runs very well, but needs some choke to smooth out, so it's a fuel system issue, IMO.
Pretty sure Dad used e-gas for years, and wasn't careful with storage times for it. Not sure if he used any additives.
I only use e-free with Stabil.
While it may not fix anything, I figure it can't hurt anything, either....plus I have it on the shelf.
Given it's 70 years old, a little gunshy of some fuel additives like STP, etc.
Marvel Schebler carb rebuild kits are readily available. Can also get new and reman carbs as well.