Mike I agree with your theory regarding the valve. Do you think the check valve would more likely be in the crankcase or in the oil tank b4 I take it apart ??
I suggest getting ahold of the parts breakdown for the saw before you start. Go after Ryobi for a copy. They are now part of MTD. If you want to find thier web site go to www.yetmans.com and click on manufacturers and then find Ryobi. Mike
