582 leaking oil (!?) from exhaust

Ok, I was expecting something more difficult to get to.

Are these a common failure point?

Normally, they will provide some resistance to oil flow, and I can see this being used to meter oil -- if stuck open, I can see how there would be too much oil going into the engine. 

Does the oil pump feed each side individually, or is there a single chamber?  In other words, will the working check valve not be opening and letting oil through if the other side is wide open?

They do stick open from time to time and flood the intake with oil... I have never seen one stick open and starve the other cylinder of oil. The valves open simultaneously. 

Ok, thanks.  I'll clean the plugs, put them back in, and see if running it a while cleans things up.

Thanks, everyone, for the advice.  I pulled and cleaned the plugs, and ran it a while.

The smoke went away, as did the dripping oil.  I don't know what the problem is, but I go out and run it for several minutes every couple of days and it's behaving fine.