Some people have had issues with low output from 361 oil pumps. I have not had any problems with oil pumps myself, except using a 361 with a 28 inch bar. After some use with the oil pump set to full, the 28 inch bar is blueing top and bottom near the sprocket tip mounts (Stihl ES bar) and the paint is burning off in these places as well.
You can replace the 361 oil pump with the full 460R (full wrap) high capacity oil pump assembly for about about $85. The Stihl part number is:
1128 640 3250 oil pump assembly
You can also keep the 361 oil pump and just replace the piston and control bolt with the 460R parts. The Stihl part numbers for these are:
1128 647 0602 oil pump piston (about $27)
1128 647 4803 oil pump control bolt (about $4)