3 Ton a/c unit?
Answers:
Chances are, if the wire are burnt on the leads, the capacitor is bad. Call a local motor repair shop to get another one. If you are real industrious, take the whole motor to them, and have them test it out for you. I used to work at a motor shop, and working on single phase motors such as that was my job. Something caused the wires to burn, so you may be wasting time replacing the capacitor, only to have to do it again. The bearings could be dry causing drag, or the windings could be burnt, as well. The shop you take it to shouldn't charge you much if any at all to check it. Sometimes, you can just replace it a lot easier that fixing it. Look in a Grainger catalog for a replacement if you want to go that route.
Good luck.
Stevo.
Other answers:
Replace it!
Replace it!
check your power: breaker panel, fuses...etc. it is not uncommon to trip a breaker or blow a fuse when connections burn. depending on how the contactor is set up...you could be feeding half voltage to the unit causing the fan to run slow. very common with trane and ge units by the way. if your breaker does not look tripped...reset it anyway. sometimes just one leg trips... if this doesnt work...then i would look replacing the capacitor.