My Murray has a 17hp Briggs I/C twin engine (42A707) that starts right up, cuts fine, but will not re-start if you shut it off. I have new spark plugs, new armature, and a good battery. When I go to re-start it, the engine just spins. I smell gas coming out of the exhaust, but I have worn out two starter gears this summer. What could be causing this?

Try cleaning the carb