Have an older Sears rider mower 502.254170b (really a Murray)... 30" blade 10 HP Tecumseh engine TVM220-157115J. Was running fine Sat , altho was idling higher than usual and also revved higher when no load on it. Anyway, yesterday I had to start it to move it out of the way in the shed. It acted like a hard start, cranked twice VERY slowly then it puked gasoline out of the muffler. Now I'm thinking maybe a needle valve or float not working and the fuel just dripped/flowed/oozed into the cylinder? I took out the spark plug and cranked but only a few drops came out. Reinstalled same plug and wouldn't start, fuel level in tank at bottom. Added some gas and it started right up. Ran somewhat rough and I shut it down to avoid any damage. What is the likely problem?