I have a Briggs and Stratton classic mower engine.
The primer bulb does not draw in at all, and the mower will not start. Dripping a small quantity of fuel direct into the carb does the trick, and the mower runs fine for as long as you like.The primer bulb then seems to be full. Leave it a few days and things are back where they were, no primer. What do I need to fix?

Richard Jones, July 2009

Clean the carb with some carb cleaner and compressed air. You should replace the primer, most likely, because the material is drying out. Cleaning the carb will ensure there is no restriction in the priming circuit.

www.vacuumcleanerhelp.com, July 2009