My stihl ms390 chainsaw leaks bar oil, so i put a threaded plug in the hole, and when i get the plug far enough in, it impedes the oil flow to the bar.
Take the bar off and clean all the pieces and parts where the bar mates to the motor. Make sure the hole on the side of the bar, where the oil gets onto the chain drivers, is not plugged. Make sure there are no burrs, on the edge of the bar from chain wear, which will push the bar away from the chainsaw body leaving a gap for oil to leak. If your bar is worn, most bars can be flipped over and used either way. If it is made to be used in on either side it will have a hole for the oil to get into the bar on both sides. Alternating or flipping the bar will make it last a lot longer.
Something else to check is if your saw has a breather hole and if that is what is leaking or it is plugged and is not allowing the tank to breath. Not all saws have this feature.
When you store your saw it is best not to store it on its side with the bar hanging down as these position will cause more oil to leak.
Even if you have a perfect fit/seal, between saw and bar, oil will still leak if it is stored in a place with temperature fluctuations. This happens from the oil expands, when it warms up, creating pressure in the tank causing oil to leak out. I always put a piece of cloth on top of a plastic base to prevent seepage onto any surface. I run chainsaws professionally for over 35 years and they all will leak when stored in place with temperature changes. Some are worst than others. Hope this helped.
Sep 29, 2013 |