B&S Quantum starts on first pull, but then refuses to restart unless sat overnight

[upupandaway]

Kerryn, When you changed the air filter, was it pretty dirty??
I ask because maybe if pretty dirty, it was working as your choke.
If the carb needs cleaning, when the auto choke is open(aka motor is warm) maybe the old filter was choking it enough that it started warm.
Try clean out the carb bowl and holes in the float bowl screw.

 

[Scrubcadet10]

Look up steve's small engine saloon on Youtube, he has a video called "how to clean metal briggs and stratton carbs"
its good. although fairly simple.