Small Engines (Lawn Mowers, etc.): Fuel leaking into carb aircleaner., briggs and stratton, briggs stratton

Question
Hi John, I have a Briggs & Stratton INTEK 205 5.5hp engine on my leaf vacuum.  It is a B&S Model: 126412, Type: 0023E1, Code: 030218FD.  Last year when the engine was new it began to run very rough and was bumping the gov and loping.  It also began to blow black smoke because the mixture was so rich.  There was gasoline running from the carburetor when I removed the Air Cleaner Cover.  The gas quit running when I closed the fuel shutoff valve.  The repair shop rebuilt the carburetor and that fixed the problem.  I am now experiencing that same problem again.  Can you tell me what you think may be the problem and is it something I can fix without rebuilding the carburetor?  I do have considerable experience with larger gasoline engines, primarily farm tractors and older automobiles.  I have never done much 4-cycle small gas engines.  In looking at the parts list, it appears to me the problem could be with P/N: 398188 what is called the Kit-Needle/Seat.  Do you think it necessary to install P/N 695157 Kit-Carburetor Overhaul?  

Answer
 Hello James:

 Try Replacing Just the Needle and Seat (P/N 398188). There are 2 Types of Needles. One is a Short Needle with an O-Ring Seat. The Old Seat has to be Removed. The Other Needle is Long with a Black Rubber Tip and Does Not Use the Rubber O-Ring Seat. If this Carburetor has the Long Needle, then Install the Short Needle and the O-Ring Seat. If the Machined Seat is Bad the Long Rubber Tipped Needle will Allow Gas to Leak by. Check the Carburetor for Casting Burrs that May be Interfering with the Floats Operation. You can View this Engine at this Addy http://www.outdoordistributors.com/ and Select the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Enter the Model Numbers 126412. Then Select the File # 12. Then Select the Folder # 126400. This will Download a Breakdown/IPL of the Engine and Carburetor. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John