I own a Stihl MS250, and have had constant problems with it. After purchase I have been instructed that this line of Stihl is really for "light" use only. I only use the saw 5-10 times per year and not too heavily, so I would think that really I would fit into this category, but I have had nothing but trouble with this saw. It smokes constantly once heated up. I thought that I probably needed to replace the gaskets, but have now found out that there is no Gasket Kit for the MS250 model. The crankcase is sealed using RTV sealant. No wonder I am smoking! To me this means that prolonged use will automatically melt this sealant and will then lead to smoking. Also, I have had to replaced the coil already as well as once it heats up, after about an hour of use, the saw dies, and will only start for a second or two and then shut off until the saw cools for a considerable period of time. To me, this saw is for the rare use in the event that a tree falls on your driveway and you have to make a few cuts. If you are planning on needing a saw to work on hour long projects with, this one is not the ticket at all!!
If anyone has a better idea on the gaskets for this model, please let me know.