Guns: marlin: model 60?

my buddy donated a model 60 marlin to me after he supposedly "cleaned" it, but it fires slow, misfires constantly, and jams like a wildcat. What could be the problem. My Ruger 10/22 fires so fast I can't keep up. I've tried the rubber band trick on both. The ruger will fire all 10 shells machine gun style with not a hint of smoke, while the marlin will get through two or three before jamming, and will be smoking like chimney? Where do I find out how to tear down a marlin and diagnose the problem? Any ideas? Although I have an Iowa address, I stay in Illinois and DO have a valid Illinios FOID card. I have no idea where to start. I don't want to tear down the marlin only to find out that there are four million parts and now I've gotten myself in hot water, so to speak........