Wiki FTW!!!! The large screw will be idle ajustment the smaller 1 at the base going in on an angle is mixture.. Sounds like its running out of fuel, take the top off the carb and letting the float hang down blow through No1 then No2 see which 1 lets the airflow freely thats the 1 you use! Now if you can,t blow air through them you,ve got a blockage and ya need to sort that out!! Also you can buy a cheap fuel pressure guage from supa junk or autowank that,ll check ya fuel pump..Not that I think that,s your prob.. Good luck You,ll get the beast haulin yet..