I do believe this is the drain screw? Both carbs are leaking from this area. IT's a very slow drip, just enough that this morning there was moisture on the top of the engine. I wouldn't have noticed it had i not smelled gas when I went out to the garage this morning. I tightened the one on the right side carb but that didn't seem to correct the situation. The one on the left carb actually seems to be seized. Any ideas? I never tried to remove them when I cleaned the carbs so I don't know why they would be leaking.