Before you tear it apart, go ahead and run a compression test and see what turns up. Even if the valves are moving, they may not be seating. If it was running before it was stored in the barn, it should still run. I'm amazed that it gets fire after that long. It could be that it's still flooding out from the original cause. Pinch the fuel line off and drain the carb bowl and see what it looks like. Could be sediments all down in the bowl coming from the tank. Who knows what's in that tank! I've seen bugs and spiders, grass and all kinds of crap, dirt, etc in the fuel tank. Do some diagnosis before you go into disassembly. Let us know what you find out and do first. Good Luck..:thumbsup: