I was tethering hay this AM and noticed that when I went up steep grade the tractor really pulled down low in 4th gear. (don't know percent of grade ) With out the tether in gear it was OK. This is the hardest pulling that it has done in 4th gear since I brought this tractor back to life last summer. I cleaned the carburetor then and adjusted it to run OK for all other tasks. Should I open the power screw open some more? It is only out about 2 turns. This baby will eat the road up in 5th and walk the hills here. This is the first time that I have had it to lug right on down to where it would have died out. Never had the first miss.