IH Farmall 656 gas/ IH 240 Utility/ 2, Super C Farmalls/ 2, Farmall A's/ Farmall BN/McCormick-Deering OS-6/McCormick-Deering O-4/ '36 Farmall F-12/ 480 Case hoe. '65 Ford 2000 3 cyl., 4 spd. w/3 spd Aux. Trans
If it's like my 450, there are adjusting bolts w/jam nuts on the actual control valve, under the seat where the linkage attaches. Mine seems to be pretty touchy, and have to readjust every now and then.