Small Engines (Lawn Mowers, etc.): lawn mower starts, then quits, briggs stratton engine, briggs stratton

Question
Hi, John.  I have a 9 year old Craftsman mower with a 3.8 hp Briggs & Stratton engine.  I can get the engine to start, and it usually runs only about 5-10 seconds before it shuts down.  Sometimes it runs longer, but the rpm goes up and down.  When I try to restart it, it will usually start on the first pull as long as I prime it.  If I don't, I have to pull it at least a few times.  I replaced the spark plug but it made no difference.  The first time I had it out this season it did the same thing for about 5 minutes, then it ran well for about an hour, enabling me to cut the entire lawn.  The gas is fresh.  I've tried playing with the throttle setting but that hasn't helped either.  It seems to me like it isn't getting consistent gas since it starts immediately when I prime it.  I'm not a mechanic, but if you give me simple directions I can give it a shot.  Any ideas?  Thanks for providing this service, John, whether you can help or not.  Don Schmittdiel

Answer
 Hello Don:

 The Carb Needs to be Cleaned and Rebuilt. I suggest you got to the Small Engine Shop and take the Make, Model and Type Code. Ask them for a Carb Overhaul kit for the Mower. Look at the Kit and if you feel you can make the repairs with my Instructions, then purchase the Kit and let me know. If not let the Repair shop do it.

 Good Luck

 Respectfully

 John