After much reworking and replacing,and cost. I finally nailed the problem of why my 12g was putt putter and stalling hills with no power. Last year I had the valves done and I installed a new ignition module. That helped but it still wasn't running like it should. I had also put a new exhaust on the tractor. Yesterday, I pulled the gas tank off and replaced all the hoses on the machine and I installed a new fuel filter. I had bought a new fuel pump from Richards last winter and when I went to remove the two screws which hold the original pump to the block, I found both screws finger tight ! Having bought the new one I replaced the pump and now the old Gravely is running like new ! I plan on rebuilding the original pump so I have a back up.. I am re-leaved that it's finally running great. Posting to let you all know to check you fuel pump screws to see if they are loose.. The lost of power and the the sputtering has me wondering if the other stuff I did was not the original issue. Anyway It's great to have my tractor running like new..