Small Engines (Lawn Mowers, etc.): 1999 John Deere Sabre Flooding Badly, briggs and stratton, fuel spill

Question
Hey Tom,

I have a 1999 John Deere Sabre 1538 HS with the Briggs 15.5hp engine model 28N707. I just got it off a guy because I thought the float was sticking. I took it apart cleaned the carb and put it back together and its still badly flooding. It was so bad that I replaced the carb with another rebuilt carb. I am still having the same concern. The flooding is so bad that its filling the cylinder full along with the intake pipe on the side of the engine. I took off the pipe and the fuel came pouring out. I got the fuel out of the cylinder by taking out the spark plug and cranking over to let it blow out. When it does start its smoking like the garage is on fire. I was just wondering what your advice would be on this or if you have seen anything like this before

Answer
Common problem with that carb, it's either a LMT, or LMK model carb. Needle valve and seat are not sealing, or the float is filling with fuel. Doubt the float as you've used 2 different carbs.  It is more than certain in the needle valve, and seat portion. I guarantee it. We do over 100 of them a year at least. The common problem is that carb has a brass seat which few people (even good mechanics) know has to be replaced, they simple just change the needle valve. THEY MUST BE CHANGED AS A PAIR ! Go to the Briggs and Stratton website the manual is there, and will guide you through the rebuild, and how to press out, and reinstall the brass seat. Don't forget to change your oil, and filter if equipped, the fuel spill over goes past the rings and into the crankcase diluting, and over filling the crankcase.   Tom