The choke on a John Deere lawn tractor aids the engine in a cold start. In order for an engine to start after it has been sitting for even just a few hours, the engine needs to be choked to start. When you push the throttle all the way up into the choke position, it closes a large portion of the air intake, so more fuel gets to the engine. When the throttle cable becomes out of adjustment, the choke may not be working. Adjusting the throttle cable will take about five minutes.
Park the lawn mower on a level surface and set the parking brake. Remove the ignition key.
Advance the throttle lever on the dash to the FAST idle. Open the tractor hood and locate the carburetor control plate directly behind the carburetor on the left side of the engine. There is a hole on the throttle control lever. Align that hole with the hole on the carburetor control plate directly behind the throttle control lever. Insert the 15/64-inch drill bit to keep in place.
Loosen the clamp on the throttle cable with the Phillips screwdriver. Pull the throttle cable up until it is tight, and tighten back down the clamp over the throttle cable. Locate the screw just behind the throttle control linkage.
Turn the screw clockwise until the end of the screw is just touching the choke control lever, which you can see by looking through the hole in the carburetor control plate, directly to the left of the throttle cable.
Remove the 15/64-inch drill bit from the two holes.