Was out last night throwing my Curado 50e and my spool tension wasn't tightening. I was using a 3/16th ounce shakey head with a speed craw, so it wasn't a crazy amount of weight. I would lock the tension knob all the down I could by hand but the bait would just continue to free fall. What could be the cause of this? I hadn't used the reel much recently so I don't know if it has always been like this, but I had recently cleaned it. It casts fine so it's not a huge deal just curious if this is an issue anyone else has come across and what I could do to fix it. 

you positive that you've got the spring and spacers back in there properly?  

The shim was my first thought. Going to check that this evening when I get home. I hope I didn't goof and put the knob back on with out the spring. I don't think I would do that, but wouldn't be the first time a forgot something. That's an easy fix if that's the case.

i'm no expert on reels, trust me.  BUT there's also not a lot to go wrong with the cast control parts either i don't think.  i'd say it's something with how you reassembled the spring/spacers.

I got home late from the river last night and didn't have time to inspect. Glad my thinking was in the right direction. Will let you know what I discover. 

Sometimes the springs get weak and need replaced. It is a relatively old reel. My CH51 did the same thing. I stretched mine just a tad to get me by until the new one arrived. 

Bad spring or missing a shim. Make sure you check under both the cast control knob as well as under the side plate bearing. 

Missing or damaged shims. If the shim is dimpled flip it over for a temporary fix