Fingers crossed--problem solved. Disassembled petcock and cleaned thoroughly. Checked seals for wear--none. Examined lever--very tight tolerance to align seals to shut off flow. Per previous post, lightly sanded sealing side of lever with 1000 grit wet with WD40. Once polished the problem was apparrent. The end of the C shaped recesses were worn down considerably, which in effect created a longer circuit which overlapped the fuel intake holes no matter what the position. Whipped up some JB Weld and built the surfaces back up and slightly shortened the circuit as well. This morning gave it some light sanding on a flat surface(whetstone)with the 1000 grit WD40 treatment. Did the install---No leaks!! Repairing things beats the heck out of buying new parts. Hope this helps someone.