OK, don't take this the wrong way - but running a saw with out-of-the-box tuning IS operator error. I own may 9 brands of saws from Jonsered, Husky and Partner (Swedish) to Echo (Japanese) to Royobi (Taiwan) to Poulan/Craftsman) (USA). They all run for years and years if you know what you are doing as far as set-up, tuning, and maintenance.
You ship those burnt saws to me and I'll see that they get rebuilt and used by Park volunteers for the next 10 years or so. They are not bad products. They were just adjusted wrong and run w/o correcting the issues. High-speed air cooled two strokes are not water cooled Porsche's, or motorcycles, or jet engines. They are their own animals.
I don't dislike your idea of older Macs as good solid tools. My family knew and shared with upper echelon employees at McCulloch back in the day. My Pop got a free Mac from one of them as thanks for family camping them on our "resources". Been there and run them for a few decades, to say the least (since a 1-40 was a "new" saw). Built mini-bikes using Mac engines. Just bought three Mac rebuilders off the 'Bay to put into circulation at the local Park for forest management by the volunteer staff. Pretty tough and parts are still readily available.
But, before you go much further into this world, learn some tuning and set-up procedures. New saw - a few drops of Marvel Mystery Oil down the plug hole and spin her over a few times to make sure the rings are wet. It'll burn off soon enough. Mix the gas/oil a bit wet for the first few tank fulls. Say 36:1 with EGD/API-TC rated oil (choose your favorite poison). Keep the chain SHARP and moving. Bogging is bad. After say three tank fulls, you can run 40:1 all you want. Don't even reach for 50:1 until you really are skilled at tuning.
If they have EPA mufflers with cats (?), they need to come off and get a bit of mod as they trap too much heat in the motor and restrict breathing. This is not rocket science, but all these motor designs were laid down decades ago, adding new heat traps to older motor designs is creating teething problems like GM cars in the late 1970's.
We eventually got through the hurdles, but it was tough for a while. Add plastic chassis and such, and heat management is a issue to be taken seriously. So opening these mufflers up by 20% with a drill and die grinder will do a lot. Usually it's obvious - open the final discharge opening, drill a few holes in the inner ports to get better flow, etc. You can get much fancier, but this will do.
Get the right carb tuning tool for each saw you own before you ever attempt to run it. NEVER trust a factory tune. It was not done at your humidity/temp/altitude - and all two strokes are sensitive to tuning to meet atmospheric conditions. Once you have it dialed, it's good for most of a season, but you have to get there first. This applies to old Macs too. The lean thing is to get past EPA regs. It's not about a working motor running under load.
What brands of saws did you burn? If Poulan, you might want to look at getting another D009 bar mount brand like Husky or something. Might as well not toss good bars and chains. They are wear items, but they have a lot of usable life. Use them and learn to dress a bar, file a chain, set-up bar oil feed, etc.
You'll do OK, but you need to not hurry and ask what works, then think your way through it. You need to "pre-flight" a saw if you want it to live. There's just no way around it. It's part of basic safety and good tool maintenance.
