Weird stuff. I had to keep the choke on all the way today to keep it running, but I let it run that way a while, raised the main idle by about a half turn, and then let the choke off a little (still couldn't let it off all the way, even with the idle set higher) and drove it around the block. By the time I made a couple of turns and put it into neutral a couple of times and revved it, it seemed to be running pretty smoothly again, so I let the choke off the rest of the way. It was running pretty fine, but the main idle was now too high. So, I backed that off to a reasonable place and it still seemed to be fine. I put it in gear with my foot on the brake, and it still ran fine. I think it was some crud in the gas or maybe something hung up in the carburetor. Maybe a good shot of carb cleaner would be a good thing. The fuel filter is only a week or two old and it looks fine (it's a clear one).
