Small Engines (Lawn Mowers, etc.): Fuel pump, craftsman lawn tractor, fuel pumps

Question
Morning. I have a B&S 18hp V-twin, model 422707, type 1522 01, on a Craftsman lawn tractor. It was running fine and then it quit. There's no fuel being pulled by the pump, a 3 screw model, and it's like it lost the vacuum needed to operate the pump itself. I replaced all fuel lines and the filter expecting an air leak. No good. How is it possible to lose this vacuum to the pump. Mine seems to be blowing air out not drawing it in. Stuck valve? It will run fine if force fed gas into the carb. Any idea's?    Thank's, Jim

Answer
Bad fuel pump diaphram? Have you dis-assembled and inpected the fuel pump?  On carbs similar to yours, you can remove the top of the carb and check to see if the fuel pump is pumping fuel.  Make sure you remove the spark plugs before working on the engine.

Below is a link for fuel pumps:

http://engines.myfaqcenter.com/Answer.aspx?p_faqid=3352&body_0$tbKeyword=fuel pump

Let me know if the link helps.