Thank you for your interest in my problem. The mower is hard to start, meaning it takes a lot of cranking. Once started it runs great. Better after I adjusted the valves. I think I have them right. I mowed for two hours today. The jury's still out on the problem. But here is the part number of the spring that I think is broken. Kawasaki 921457001 SPRING . What do you think? This spring is part of the mechanism that opens the exhaust valve at low RPMs to allow for easier starting.