Small Engines (Lawn Mowers, etc.): B&S problem, little engines, debri

Question
MR. Jones

 I have a 2002 4hp B&S maodel 10a902 type 2189. I just got it out to start mowing this year and it runs very strange. The motor will rev up past the normal idle, then drop back down to almost stalling. This is constant from as soon as I start it up. I replaced the plug, oil, and filter this year but i dont think it is any of those three. I also pulled the carb of the tank an shot everything I could see with carb cleaner. I have a maintenance manual, but it offers no trouble shooting. I dont know much about little engines, but I am a jet engine Mech, so i am pretty sure I can catch on

Answer
Either you have a leaky intake gasket/o-ring or the carburetor is obstructed.

Is it a float style carb?

These newer, non adjustable carburetors are very, very sensitive.  Any small debri, even a drop of water, can cause them to malfunction.

Do you have any air compressor?

Let me know the carburetor type and if you have a compressor.
Eric