Year and model maybe helpful. some helped me out with an older model a couple of months ago with the same problem, I cleaned and reassembled a ebay parts box saw. It would not oil either, Mine had a oneway check valve coming off the block under the bar/chain cover. this valve alowed crankcase pressure to pressurized the oil tank so the oil could be forced to the bar. (this is why old saws leak the bar oil out IMO the tank is still pressurized siphoning all the oil out) Mine also had a last chance filter that was toast. Fixed mine