EE WAS USING A CHAIN HOIST TO REMOVE AN ELECTIC MOTOR FROM ITS BASE. THE PULL FOR THE HOIST WAS DIFFICULT TO OPERATE. IT HAD BEEN CLEANED IMMEDIATELY PRIOR TO USE DUE TO MATERIAL BUILDUP IN TH E HOIST MECHANISM HOWEVER THE HOIST STILL LOCKEDUP CAUSING EE TO STRAIN HIS RIGHT SHOULDER. DID NOT REQUEST MEDICAL ATTENTION UNTIL 8-27-03. HE WAS SENT TO SPECIALIST WHO DIANOSED ROTATOR CUF