McCullough plugged up oiler

[n2wood]

I have a McCullough chainsaw (approx 7 years old), which appears to have chain oiler problems. I can not press the manual thumb oiler in (I reckon oil doesn't compress very well) Something appears to be plugged, since the automatic chain oiler doesn't seem to work either.
I disassembled the oiler piston, but do not see anything wrong. Should blowing air into the chain oiler exit port clear out any blockage or does this require something more extreme like angioplasty?

 

[Bills Oak]

Plugged oiler

I would try to shoot WD 40 through the entire assembly backwards first--take off the oil filter/screen & see if you get flow from the pump backwards & then go the other way--most likely just a small pice of crap stuck somewhere--take it easy ony use a little air pressure if you must--you might do damage or blow out a line!. The WD 40 flush usually works for me---Bill Irvine