This is somewhat typical of these engines, and you can spend thousands chasing this ghost or just modify your operating habits by giving it a bit of throttle right after it starts on a hot start.

This condition can sometimes be tuned out by adjusting the duty cycle to a lower value to achieve a slightly richer base mixture, but if it cold starts okay, this may not help.

I consider an idle duty cycle of 45-50 percent to be ideal, but if starting behavior is a problem - either hot or cold an idle duty cycle of 40-45 percent might help.

Duke