My 27 Kohler Command sometimes won't start once it's heated up. I had this issue last year and replaced both coils and cleaned the carb, but today it happened again. Drove for about 20 minutes at part throttle then shut it off. It wouldn't restart. White puffs of smoke from exhaust when cranking. Eventually I got it to start by combination of choke and partial throttle.
Got back to the launch and shut it off and tried again. It fired right up. Did this a few times, no issues.
I don't get it. Seems like vapor lock. Any suggestions?

The white puffs of smoke make me think it was flooded for a minute. Possibly need a carb clean with a new needle and seat. I would take a spare spark plug with me and the next time it does it remove spark plug cap and plug in the test plug to verify spark wich would verify its a fueling issue

I agree with that theory. My plugs are more black than brown. I don't know how to lean the thing out. I've cleaned the carb numerous times.
I'm running 87 octane no ethanol fuel. Gonna try going to a higher octane.
I also run just the Champion® RC12YC plugs. Maybe I should change?

I was thinking maybe the carb is dripping fuel into intake when you turn it off