I recently purchased a 1983 300sd w 258K. It needs a little attention. It is very slugish off the line (below 1500rpm). I have replaced the battery and glow plugs to fix its starting issue. Also I have replaced both fuel filters and adjusted the valves. This helped some. I noticed it has quite a bit of nailing form afew of the cylinders at low rpm. I did a diesel purge and that helped a little. Yesterday I removed the injectors, disassmbled and cleaned them. There was little change. I have also checked the banjo bolt and line. It was slightly dirty but not blocked. I cleaned it -still no change. Lastly I looked at the injecting pump timing. As best as I can determine it is retarded(15 BTDC). I have tried to adjust it with little success. One article I read said to push the pump towards the motor to advance it. The other article said the opposite. Which is correct? Also when pushing towards the motor (I believe this is the correct direction)it seems there isn,t enough adjestment to get to 24 BTDC.This is w/o the lines atached etc. Is it possible the pump was not properly installed to give enough adjustment? It looks like the timing chain is recent( only 1.5 deg stretch) What do you think?

Thanks!