runs rough when hot

[tim24fan18]

I have a 2005ish mtd tractor with a 18.5hp single cyl els 500 series briggs..seems to run like its out of fuel..but I have changed filter...took the bowl off..there's no float in there..weird.. took the fuel cap off new plug..everything..I can mow for 15min then wants to die..loosen the fuel cap then tighten it again then runs fine.I even drilled a bigger hole in fuel cap....can someone help me...u think it could possibably be the coil..thanks

 

[mostly_gas]

Does it have a fuel pump?