I have a Scag SWZU 52" walk behind mower that has issues with the Ogura clutch. It engages slowly. As I understand it this clutch can be adjusted by resetting the air gap to .012 inches. I readjusted that air gap by tightening the three nuts until there was slight resistance when inserting the .012 gauge, but this didn't fix it. The mower itself shows 2025hrs. At 1500hrs I replaced the 21HP Kawi with a 23HP Kawi engine. I also replaced the clutch, belts, pulleys, spindles, etc. There has not been any issues with the clutch until just recently. I have come to the conclusion that maybe I was not explained the proper procedure for adjusting the air gap. The local dealer wants "$50-100" to adjust it for me, and they can't even guarantee that this will fix it. Also, I realize that with a new clutch costing $150-225 I could just replace it and be done with the issue. I guess that I would rather learn how to make this adjustment properly. Does anyone have experience that they would like to share?