I have a Scag cub (2008) with only 116 hours. It's for home use only (1 acre). I have changed oil, air filters, oil filter and plugs along with blades every year before first cut. Problem is, this year, when i engage the blades the mower bogs down and runs at about 1/4 of the rpm's it should be. If i push forward, it wants to bog down until it stalls. When idling before engaging blades, the mower runs fine. Any suggestions? Would like to try anything before taking to a dealer and getting raped on the bill. Thanks!!