Need a little help. Won a mower at a charity auction for my Mother in Law. Don't know where they got it from- no stickers on the unit. Starts terrific, continues to run and wheel drive works fine. Having some problems with the clutch when I engage the mower blades. The engines rpm's drop off and it will stall most of the time when engaging the blades. I adjusted the slack of the clutch spring under the deck and now at least I can feel the positive click of the clutch engaging correctly when i push the lever forward and it stays engaged until I release the safety brake handle (when I can get it going) which is what it is supposed to do. Throttle is 4 position and I am using the 3rd setting so it should be getting plenty of rpm's. However, I'm still thinking it's a throttle or choke problem. Any thoughts or experience before I try calling one of the local JD dealers service department for help? I did try calling the venue where I won the auction to find out where they got the mower donated from- it was donated by a local Foundation with an answering machine. Thought I was doing a good deed for my MIL, but maybe it backfired. Thanks