Hot starting question

just got over the same prob. gas still in the carb but when hot she would crank my battery out of juice.
first of all this only started to me when i changed my t-stat from a 160 to a 195 still no sighn of boil over. but hard start when hot or warmed up.
my fix was a 1 in phenolic spacer its fiber not plastic or alum. when my motor is 200 degrees i can still grab my carb without it burning my hand.
or i think i could of just put a 160 back in it lowering mi temps. 35 degrees. had no problems before.