Small Engines (Lawn Mowers, etc.): Mower Problem, briggs and stratton, hp briggs

Question
I have a 17.5 HP Briggs and Stratton motor that is giving me problems. The motor will crank up, and run. When it is placed into full throttle the motor dies. If you pull the choke it will run, even when it is warm. It looses power drastically when under a load. It will idle, even when warm, with no choke, but when sliding the throttle toward full it dies. I have opened the breather and it seems in the carb there are two butterflies, one lower in the carb, and the top is the choke. The lower is not doing its job, and opens to full open, thus the choke butterfly is doing it's job. The lower butterfly seems to be tied into a governor or something, what would you suggest to correct this problem?

Answer
Hi Harold,

You mention that the lower butterfly opens to full open.  At full throttle, it should.  If it doesn't, then there might be a linkage spring broken and missing.  If it does open, then there is a lack of fuel flow to the engine, especially since it runs with the choke on.  The carb most likely has dirt, debris or gummed fuel.  You will need to remove the carb, disassemble it, clean all the small internal openings and blow it out with compressed air.  

Let me know how you make out.
Michael