Chainsaw Repair

The one thing I have not tried or done is dilute or thin the bar oil.

Owner's Manual:

http://dl.owneriq.net/6/63845e93-f5b5-8c74-c535-6abaf291506c.pdf

McCulloch Branded version of this chassis (4600, 4900, etc.) shows the best breakdown of the oiler parts.  Yep, the oiler shaft gear looks to be made of plastic.

http://www.manualslib.com/manual/466151/Mcculloch-46.html?page=4#manual

Page 12 contains the procedure for bar oiler adjustment on the Craftsman version.  I think it is provided to control how much oil is to be leaked onto the bar during operation