Probably the little holes on the bar that mate up to the oil hose discharge on the body of the saw are clogged. If it's leaking out the bottom and not getting on the chain, that's usually the problem. Take the bar off, and give it the pressure washer treatment all round. If you have air, you could just run some air down the channel. Also, look above and below where the bar attaches to the saw on the bar. That's where there should be a little hole on each side.
If you set the bar down with the bolt hole area to the right, the hole should be above it. Some bars have bigger oil holes than others, so if the bar is really grimy it might not be obvious. Clean out the hole. A picture would be a big help...
http://i22.ebayimg.com/03/i/07/c0/bb/63_1_b.JPG
Look to the left down low on the picture linked above, you'll see the little hole to the right of the two vertically oriented holes. That's what's probably clogged.
I'd rather run out of gas before oil, but if the chain seems too dry, maybe the pump needs turned up. My 2159 seems to use about the same ratio, and the chain stays pretty well lubed, IMHO.
Shouldn't you be on the Merkur club forums?
--Andrew
88 XR4Ti