This is a verticle shaft Briggs on a Jacobsen tractor. I didn't have a spark so I replaced the coil with a magneto coil and took out the points and condenser. I still had no spark so I came to HobbyTalk and found out I had the new coil upside down. Mine has nothing printed on it to tell a nut like me which way to turn it. Anyway, I flipped it over and the spark came thundering through. I opened the gas line and the engine started right up. It was stuttering and puffing black smoke so I tried to adjust the carb. I could get it running smoothat higher RPM, but when I drove it around (no mower deck attached) it would go back to rough running and not good power. I stopped the tractor and noticed that fuel was coming down from the intake neck just below the long screw that attaches the air cleaner. The float is free but maybe I need to look into this carb. Thanks for your suggestions.

Sounds like it might just be time to take the carburetor down and give it a good cleaning and possibly install a rebuild kit