I have a 99' exmark that I believe is experiencing cluch issues. The problem is when I go to flip the switch to engage the deck, it takes about 10 seconds before the blades reach full rpms. Also, if I mulch up leaves or heavy grass the blades really reduce rpms and I have to wait until it powers up again to begin cutting. I was wondering if this is common sign of a clutch that is spent or are they other things to try first? Any suggestions? Thanks, Eric