The oilers are very sensitive to small bits of saw dust getting into the one way valves that feed the oiler. My old Poulon Micro XXV had a very similar problem. The oiler on it works from the positive and negative pressure pulses in the crankcase. This sucks oil through a filter in the oil tank through a one way valve diaphragm assembly and then on to the oiler where it goes through another one way valve. The one way valves are a steel ball with a very light spring and a very small hole. Mine was pressed together and was plugged solid with something. I'm guessing it was sawdust as there was always plenty of it around. Of course there are no parts available. I tried to clean it with solvent, a thin wire and some air pressure, but never did get it to work. I got mine fixed by rebuilding the one way valve. The spring and ball were still good. I carefully cut the plastic body apart and spliced it together with some brass tubing from a hobby shop. It comes in a wide variety of sizes and one just fit inside the valve body. The plastic tubing in the oil tank was very brittle and cracked too, so it was replaced too. It can be done, if you are willing to tinker with it. If time and reliability are important, then get a new saw, and keep that bar oil clean. It's real easy to get a chunk of sawdust in there when refilling the oil.
