The culprit is the seal on the outer cover. These take a beating and do fail. Not a bad job if you have access to an impact, and a press. It requires removing the primary, and secondary clutches, draining the oil, and removing the inner cover. The clutch housing needs to be pressed out to gain access to the seal. They load from the inside. Another thing to look at is the fixed spacer as they sometimes develop a groove. The cover gaskets are reusable so be careful with them, the seal is a low dollar item, but a pain to change! The Clutch nut that holds the secondary on should be replaced also (I've found that they lose grip after repeated use, and allow the fixed plate to come off) For a free service manual go to K&T lawn equipment. I usually see about 3,500-5,000 miles on seals before they leak. The belt can be cleaned with soap and water. Clean the clutch surfaces with brake cleaner. On the inner cover, just take that to any shop that has a press and they will be able to help!