I've always thought that every part on a chainsaw had some usefulness or they wouldn't go to the trouble of installing the part from the factory. I've had several 290s in my little shop that the owner had removed the pre-filter from. I've always replaced them and mentioned it to the owner but now I'm wondering if I was right. I have one on my 390 and plan to keep it but should I do that on a customer's saw?
