I opened the case of my Sthil MS311 chainsaw and found a recessed screw in the case, but I cannot find where it came from (saw wrench head for scale). It seems to be a something used to hold liquid, because of the rubber gasket. The saw ran fine for a long time (about a year). It's been acting up lately, not sure if this is the cause. By acting up, I mean it starts fine, but it seems like the chain isn't getting enough bar oil, causing the chain to bind up.
I searched though the parts list on the usual sites, but cannot find it.
Any idea what it is and where it goes?
Best Answer
The rubber gasket is a vibration isolation mechanism, not a liquid holding mechanism, based on experience with the parts of my Stihl saw (different model but those parts are similar.) All the mounting points between the handle/frame and the saw motor use those rubber-mount nuts.
While lacking a convenient exploded parts diagram, the manual I found does have a list of things to check when the bar is not getting enough oil.
https://stihl.partsmartweb.com/Catdata/EMP_IMG/STGSTH/Images/SERVICE/00590215.PDF