Hmmm...lots of Kawasaki threads today. I have a FC420V on an Encore 48" belt drive WB. After 25-30 minutes of use mowing at WOT/3600RPM, the engine will start to hesitate/bog down. RPMs drop to the 2400-2600 range, and if you don't immediately remove load from the engine (disengage blades & transmission), the engine will die. If load is removed, engine will struggle back to 3500-3600RPM, and then bog again when load is reapplied. If you allow the engine to die, it will restart on the first pull (with choke), and then repeat the bog/die behavior as soon as you reengage load. Yesterday I went through this cycle with it, trying to get it to restart and run, for about a half hour after it started acting up. Eventually just parked it. Pulled it out again today, same behavior after the 25-30 minutes of use. Let it sit for about 30-40 minutes while I finished up with a 21" mower and trimmer, then started it up again. Ran for about 10 minutes and then had the same behavior. I'm thinking it's got to be something thermal as the engine heats up. Anyone want to point me towards a direction...carb or coil/ignitor? Fuel appears to be consistently getting to the engine, based on the fact that it always will restart on the first pull, and the clear fuel filter is full. Engine is a FC420V-FS15, E/N FC420VD94123. Thanks in advance for ideas.