Thank you all for the good advice. In my rambling through cyberspace I stumbled across the solution in a YouTube video, "Briggs and Stratton 300e won't prime, runs with starter fluid - Easy fix." I had been pushing the primer bulb 5-7 times but it seems that for this engine you need to push the...
I've cleaned the gas tank, replaced the sparkplug and the carburetor but it won't start unless I remove the air filter (also clean) and spray started fluid directly into the engine. Then it runs fine (without smoking) until I release the kill switch. It won't restart without spraying the starter...