When you set to 10*BTDC, do so with the vacuum line to the distributor disconnected and plugged. Once set reconnect the line, should recover to somewhere around 2-5*ATDC, that should do you right.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.