Small Engines (Lawn Mowers, etc.): Briggs and Stratton 11 Hp., carburetor overhaul, carburetor adjustment

Question
My problem is the carburetor on my Lt11/36 Craftsman Tractor, with a B.S. 252707 11 Hp motor. It will start and run but it does not affect the running if I turn either or both the low speed mixture jet, or and the high speed jet in all the way. I have checked the float level and it is set to factory specs. All airways and orifices are clean. Help please. This is driving me crazy. It also seems that the motor is running rich, lots of carbon.I would like to thank you in advance for any help you can give me

Regards,
Bill Kelly

Answer
Are the carburetor adjustment needle seats damaged?  The seats can be damaged is the adjustment needles are screwed in too tight.  The manual tells you not to screw the needles all the way in.

You can replace the high speed jet, the one in the float bowl, but the low speed seat is machined into the carburetor.

Have you ordered a carburetor overhaul kit and installed the new adjustment needles.  Is the float, when you hold the carb upside down, level with the carburetor body?

Eric