Sounds like it is tough going. Are you lucky enough to be able to pull the axle w/ the wheels on? Is it imperative to get the wheels off? I know that seems like a stupid question- but I'm not sure what the nature of your repair is. IE with a bit of work many times you can tube a tire on the machine if you have to.

The 'hot wrench' always works for me. Maybe you are
not getting it hot enough, but be careful of seals,
and of course your fuel supply, (we're talking cherry
red). Oh, and a 'BFH',](bigger f-in hammer).

Yes, using one of those little propane torch heads on a small bottle, will definitely NOT get it hot enough to get the wheels to slide off.
If the BFH trick fails, you can always tilt the machine up at an angle and pry the tire off with several flat bars and long screw-drivers!
And, if you ever buy a new one--first thing to do is slide the wheels off the axles and apply some of that silver anti-seize grease to it, then put the wheels back on. This is also good to do on anything with removable, slide off, hubbed wheels.

I've been going through this trying to get a Simplicity unstuck. First wheel tooks weeks of PB Blaster and heat, and only then could I slightly rotate it with a pipe wrench and a huge extension bar. Eventually got it off. The other one's still stick tighter'n hell.

I just bought an older Simplicity 860 which starts fine when cold but seems to be running rich and cuts out after a few minutes.

Does anyone have mixture adjustment instructions or a repair manual?

Wolf.