You might check to make sure the throttle/choke linkage fully closes the choke butterfly when in the choke position.

Current model year tractor...or an older one? Current model has a Kohler Courage engine...and I believe a Choke/throttle control all-in-one. (Some older models may have had a separate choke control and a B & S Intek...) With the Kohler, make sure the choke throttle is up past the "notch" that indicates the choke being engaged (should be able to 'feel' the notch). Removing the air filter would verify it is not dirty and (perhaps?) allow a visual inspection of the choke operation (it should open/close as you pass the "notch" mentioned above) If the tractor engine is warm (or perhaps even in hot weather) you can try to start it without using the choke. The gas' vapors are more volatile when things are warm. Cold weather or cold engine...the choke will need to be working correctly as the previous poster had suggested.

Any other symptoms? Or just hard starting? And has it always been thus? Or is it getting worse?

make sure choke plate is closing tight,make sure you have a clean plug,if it has a lot of time on it remove head clean carbon, ck valve adj.Rick

Hi catleys
These guys are hitting the nail on the head about about the choke butterfly. My tratcor wouldn,t start after a week. I found the little clip that held the choke cable tight wasn't holding it tight. I took a screwdriver and tightened it up and closed it right away. I had to adjust it so the butterfly was was fully open in the open position and closed when you put in in th closed position. It't been 4 years now and no problems. I hope this fixes yours. Good luck to you (PAP)

Thanks to you all for taking the time to offer up your thoughts!!! Seems to be pretty consistent RE where to check for an issue, and I will do so. KUDOS to you all for such super synergy, and being willing to point me in a resolution direction.

I have a 42" Troy-bilt Bronco lawnmower. About 3 years old. Model number 13WX78KS011. When I turn the key to switch on and start the engine, nothing happens. No chatter from the starter solenoid or any effort to start from the starter. Just purchased a new battery. Could the safety system cause this problem? I have verified that I have a good hot battery. The starter will operate when trying to jump start however the engine will not crank which indicates that the spark plug is not receiving any electrical spark. what is the best way to trouble shoot the safety wire system. One headlight does not work. Any suggestions are assistance will be greatly appreciated.

Try pushing the pto engage lever backwards. Mine done the same thing & the lever trips a switch but wasn't doing so unless I pushed it back all the way, held it then turn the key