Does anyone know if it is safe to raise the rpms on a 6hp OHV Kawaskai engine (found on the John Deere and Toro 21" mower) from the factory setting of 3350 to 3600. My dealer did this to the Kawasaki engine I have on my John Deere. This has increased the speed on my mower tremendously along with the cut. However, the engine has become quite loud to the point where I am concerned about its long term health. Any ideas?