I'm not sure about your ignition

but on the carb, i would look closely at the checkball under the squirter sealing. that check ball is there to hold fuel near the squirter, if there is any gunk buildup, it may be bleading down.

another thought is when the engine gets hot, todays fuel boils very easily, while your driving, boiling gas may be pushed out the squirters and you don't know it then when you mash the pedal there is no gas sitting above the check ball

another thought, is the weather may have turned cooler and the carb seems leaner to the engine and you may need to open the A/F screws a bit.

If you have the balls to take drill bits to the carb, PM me and I will tell you how to take care of the bog forever