Are you in the mood to dig in or just want some possibilities for pricing a shop? It does take some knowledge and some tools. But we are all glad to try and help. It's going to be questions, observations and tests. Can be anywhere from "out of gas" to dirty air cleaner to valves at this early stage. Recover? Did it "recover"? What did it do on the way home and at home? What is recent history of work done? Starts? Idles? backfires a lot? did it once? more? For now, Visually check for loose or burnt plug wires or ignition wires. See if choke butterfly is stuck. Any gas leaks at carb or other, leave gas cap loose next drive. Observe any other info you can give. Backfire is a good clue so describe specifically how often and if "backfiring" at carb or tail pipe or both. And do you really mean backfiring. Chitty Chitty bang bang?

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn