Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Welcome to JUST ANSWER small engines, let me try to help you !! I don't know it all, but maybe together we can get you a satisfactory answer!
Engine make and model? Single cylinder? Plugs, so I assume it is a twin engine. Do you have a voltmeter to test battery voltage when starter is engaged? Is engine spinning, just not starting?
Twin Briggs usually not hard to start. That is why checking battery voltage is good idea. If voltage is above 12.5 volts before trying start, and drops below 8 volts, the starter may be bad! Also a compression test will confirm if there is too much compression. Should be 100 psi or less.
Valve adjustment might help, but I would check voltage and compression first. Valves set at .004 to .006 inch, intake and exhaust, and from what I know, the closer to the .004, the better the compression release works.