Thanks for posting this. I am having a similar problem. I have a 250 with the single barrel and it was stalling out and flooding. I changged the filter, it ran great for a week or so. I went down a road in my area that was dug up and as soon as I pulled out on the main road it flooded and stalled. I was looking at it this weekend after changing the filter again and I noticed the gas coming out at the base of the carb. Now I guess I will be checking out the float on mine. I bet garbage from the tank stirred up from the bumps have clogged the carb.
Wow,that's weird! I wouldn't think you'd have that in a "new" carb. You can get real good gas filters at most auto stores. Just ask for them at the counter. Those cheapo plastic ones keep out small birds and rocks,but not much else!