Long time lurker, but I have a problem that I need help with. On my 318, as I am mowing with it, the throttle will slowly go from WOT to half throttle in a matter of about 30-45 seconds. I think the problem is the little spring that holds the throttle. I am thinking that maybe the spring has lost its tension and is allowing the throttle to move by itself. Does that sound right? I looked on the JD site to find the spring, but failed. What do you guys think?