Small Engines (Lawn Mowers, etc.): B&S 98902 Engine, briggs and stratton, return valve

Question
I can not get the primer to pump. I have removed the rubber primer, I can see the check valve, I guess this could be the problem but it appears OK, how do I replace this, is there another non return valve somewhere that stops the fuel going back to the tank. This happened once before, I removed the top of the carby, put the top back on and it then primed OK and ran well, this did not work this time.
Model 98902 Type 0385 Code 01 94110951

Answer
 Hello Robert:

 From your Description and from Looking at the Breakdown/IPl of this Engine, I Suggest the Carburetor be Cleaned and Rebuilt. If this Engine has the Plastic Carburetor and Cleaning Doesn't Help, then Replace the Carburetor. You can View a Breakdown/IPL of this Engine At this Addy http://www.outdoordistributors.com/ and Click the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Select the File # 9 at the Bottom of the Page. Then Select the Folder # 98900. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John