Free play is irrelevant.
What you really need to look at is pressure plate departure. I shoot for .060" with the pedal fully depressed. Free play ends up being what it ends up being. Now this does assume your entire clutch linkage setup is not all wore out and is in good condition. If it is not fix that first.
When troubleshooting, I usually start with the easiest thing to do first and work my way to the hardest. Clutch adjustment is the easiest to start with. It sounds to me like something is keeping the clutch disc engaged. This could be a number of things, Clutch adjustment, Pilot bushing not installed properly causing the input shaft to bottom out or just be too tight, loose or damaged linkage, disc not sliding on the input shaft, Etc.
