I started the engine in my '24 and went to switch it to mag but accidentally switched it to off for a second or so. The pistons were still spinning a little, and I switched it back to bat to start it again. BIG mistake. Made a really really loud POP! and quit. So I started it again and it was running for a bit and it quit on it's own after about 30 seconds. As it was running I noticed it sounded really weird so I looked it up and whattaya know, I blew my muffler open. But what I'm more worried about is that it won't start now. I read that other people have had their muffler blown open, but didn't see anything about them not running anymore. What should I do?
Since it ran for 30 seconds, then quit, I'd suspect a fuel delivery problem. Check out your fuel system from tank to carb.
It sounds to me like your switch is getting wore, or needs the prongs bent back into shape.
Yeah, those thirty seconds of run-time mean you didn't break anything ruinously expensive (like the crankshaft). If cars are anything like airplanes—and they are—you can get a big backfire from a lean mixture (scares the heck out of passengers, but if your passenger happens to be a pesky in-law, the temptation can become too great to resist). It's too simple and easy a thing not to check before you do anything else. Such leanness can be caused by the kind of problem Mike mentioned.
(For a story on what else can scare the heck out of a pesky in-law in an airplane, send me a PM).