pulling hair out in va.

have a bob-cat with 20hp engine about 1300 hrs. when cold runs great after about 20 minutes starts bogging down like it is not getting gas. so this is what I have done so far replaced fuel pump all hoses and filter. same problem after it gets hot can let it cool down and same thing happens. last thing I did was pull fuel connecter off top of tank slid new gas hose into tank
left about 4 inches out and put new fuel filter to that and put new fuel line to new fuel pump. guess what had same...

pulling hair out in va.