That even further proves my theory of too stiff a spring.

WOT in auto = main jet feeding... lots of gas. Slam on the brakes, auto tranny disengages, engine slows fast, no air flow, slide closes, unused/badly atomized gas fouls the plug.

If in ESP, the tranny will not disengage so the revs won't drop near as fast so the slide stays open longer.

Maybe I'll email servicehonda to see if they can get me a couple springs...

 

If you pull the air box and watch in the carb throat, you will see fuel pulsing up the needle jet and pooling on the floor of the carb...

 

Is this at idle? Or what?

 

What you are explaining sounds like a flooding condition. When you are reving and get out of the thottle the gas pumps a huge load of fuel to a motor that is not able to burn it because the revs have come down so fast. It sounds like it is choking itself with fuel. That would be a hard one to fix in my mind. You would have to lean out the top and that can't be good?