I tried to mow my grass the other day, and when I pulled up the knob on my Troybuilt riding mower, to engage the PTO, it acted like it was going to engage, and then didn't. The whole attempt lasted only a seconds. I tried again, several times, and it did the same thing. I checked to see that the mower was not in reverse (which causes the PTO to disengage), and now I don't know what to try. I'm sure it's probably something stupid I'm overlooking, but while I'm trying to figure it out, my grass is getting taller and taller. Maybe a wire is loose, or a switch is messed up, or something more serious. Can you help me?
Mrs Fix-it :(

Check your safety switches.

I have a MTD yard machines lawn utility vehicle. When I put it away last fall it worked fine now the blade will not engage at all but the machine itself runs great. We WD 40'd all the pulleys, all belts are in new condition, and we also tried adjusting the spring and nothing. Acts like its not even connected. Any ideas?