Are you pulling and pulling and then FINALLY your lawn mower decides it wants to start?
This is a pretty common problem with a Troy-Bilt lawn mower with a Briggs and Stratton Overhead valve engine. After a while the valve lash will become tight and not allow the valves to open far enough to let fuel in and exhaust out. If not enough fuel comes into the combustion chamber, then it will not ignite and burn properly.
If you are mechanical by nature, remove the valve cover and set the engine at Top Dead Center and check the valve clearance. One these small engines, the intake is set at .004 and the exhaust at .006 to have them run at their best performance.
Adjust the valves if they are not in specifications and reinstall the valve cover with some Triple Bond sealant. Let it dry for a few hours before you test run the engine to see if you have solved the problem.
If after your repair it still is hard to start, check the fuel and choke system to be sure that they are working as they should.
If you need a Troy-Bilt small engine mechanic to help with your lawn mower, visit our Locationspage to find a shop near you.