I have a Stihl 029 Super with an 18" bar. The Manual says you can adjust the chain lubrication with a screw on the underside depending on cutting conditions such as the wood your cutting. I assme that would imply that some types of wood might benfit from a better oiled chain. But what does that mean? I'm into a really big red oak, that's got about 30' of 24" to 30" diam trunk. I would think I would want as much chain oil as possible. My sharpening skills are still being sharpened though I now seem to be able to get mostly nice chips after sharpening each time. An oak this big is tough sawing though. Sometimes my saw will be pulling through really well and then its as though it just stops biting in the kerf. If I nose it up or down a bit it will grab hold again then a bit more and the same will happen. Can this be from too little chain oil?