I've read a lot of threads on this issue. I've replaced the ignition coil, the auto-choke spring, battery, spark plug, and filter... The engine starts fine when cold... every time. I noticed that when it is warm, the choke is open (as I believe it should be). But the engine will not start unless I close the choke. When warm, it will only start if I put my hand over the intake (forming a choke with my hand). Fires right up. How fast should the auto-choke reclose after shutting off engine?