Motor is hard to start after warm up

When the engine is hot and you are having trouble starting it does the cranking slow down as though the battery is a little weak? If so it is a sign that your initial timing is a little too advanced. Back it off 2° and try it again. If it still cranks a little slow back it off 2° more and so on.

I set my idle mixture from scratch like this:

Fire it up and hold the throttle open to keep it running for a couple of minutes. Once it is a little warm slowly release the throttle. If it starts to die, slightly tap the accelerator pump arm and see what happens. If it improves you are a little too lean so back out the idle mixture screw 1/8 of a turn. If it gets worse or craps out you are a little too rich so turn the idle mixture screw 1/8 of a turn in. Keep tapping and adjusting until it is idling good at the correct RPM and the slight taps have little or no effect.