1120 series saws (009, 010, 011, and 012) use a pulse operated oiler to lube the chain. This differs from most Stihl saws that use a gear driven oiler. The oiler is a cartridge that is attached into the crankcase of the saw. Before you do anything- including draining the bar oil, remove the exhaust screen from the exhaust outlet and be sure its not clogged with carbon. This got me once and I won't say how long I messed with the oiler before I figured out the real problem. If the exhaust screen is clean (or wasn't there to start with), put it back in. Recheck the oiler function- it often takes 10-20 seconds of running to get the pump primed and functioning. Still no oil output? Drain the bar oil tank and remove the clutch cover, bar, and chain. Set the saw on the bench clutch side up and clean off the area below the bar stud so no debris gets into the soon-to-be-opened oil tank. The oiler is the aluminum cover directly below the bar stud. It is about 1 1/4" round with one flat side. Remove the 3 slot screws that secure it into the crankcase. Gently pry the oiler assembly free of the case- it is about 2" long and has a hose attached to its inner end. Try not to damage the gaskets- usually you can save these. Once the oiler is free of the case, slowly pull it out and be sure its output hose isn't broken. One end of this hose attaches to the nipple on the inner end of the pump, the other end attaches into the crankcase where the bar oil is supposed to come out. It is U-shaped and is easy to replace if nescessary. The hose gets hot and brittle and often just breaks. Remember, these are older saws and rubber products will degrade. If the hose was intact, remove it from the pump and clean the pump off. The pump is easy to disassemble and clean. There is a spring inside it, so watch where it comes from when you remove the pump cover and put it back as it was originally. The pump diaphragm and gaskets rarely fail. You can clean everything and reassemble & test it. Often a thorough cleaning solves the problem. If not, you'll have to replace the diaphragm and gaskets- replace the hose too. I have had mixed results rebuilding these pumps- sometimes they just refuse to work. Check the cost of a new pump before you buy rebuild parts and consider your options. Hopefully a thorough cleaning will solve the problem. Good luck, and welcome to AS.