I just picked up a used Curado K for $90 on eBay. Took it out yesterday for the first time and it was great, but I noticed a couple issues. First, the thumb bar has an issue where if you even just leave your thumb on it while it is depressed and try to engage the reel, it sort of clicks and stays halfway between up and down but it still not in gear. Also, there is a bit of a sound when I reel, and it seems to be something with the guide? Can anyone help?

Sounds like you bought someone else’s issues.  I’d inquire about returning it.  Or reach out to Delaware valley & see if he can help.  

20 minutes ago, bass.slayer69 said:

.First, the thumb bar has an issue where if you even just leave your thumb on it while it is depressed and try to engage the reel, it sort of clicks and stays halfway between up and down but it still not in gear. 

A lot of reel would do the same when you have light pressure press on thumbar when engaging.

Sound when reel might come for a couple of thing, dry bearing, dry worm gear or even main gear itself and too much spool tension. Use drop of oil on spool bearings, worm gear and spool tension cap to see if it help. Otherwise the reel might need some service. It is a good practice to clean/service the reel right away  when you buy used one.

Just as others mentioned, it sounds like this reel needs deep cleaning and new grease, especially inside. You could send it to professionals like DVT here, or it could be a fun winter project for yourself. 

That sounds like a tired reel. My guess is the noise is worn worm/pawl. 

1 hour ago, Deleted account said:

That sounds like a tired reel. My guess is the noise is worn worm/pawl. 

Try tightening the pawl cap with a flathead screwdriver, also sounds like an issue with the clutch pawl assembly for the thumb bar. Could be some grit in the worm shaft. Should be an easy fix if you're comfortable taking the reel apart, if not just send it to a professional. Be sure to leave a negative seller review on Ebay to warn others. Good luck.

Thanks for the help everyone, going to just do a deep clean and see how it reacts to it.

Just wrapped up a good oil and rinse, the noise while reeling has gone away and it just feels a lot smoother overall. Thumb bar issue is still there but I can live with it for getting a quality reel for basically half off. Thanks for the tips everyone, might try and solve the thumb bar issue if I can figure out what to do.

4 hours ago, bass.slayer69 said:

Thumb bar issue is still there

Did you pull the pinion yoke and grease the ramps, clutch mech to frame, and thumb bar pads? Something's dry or hanging up within that list.

23 hours ago, bass.slayer69 said:

Just wrapped up a good oil and rinse, the noise while reeling has gone away and it just feels a lot smoother overall. Thumb bar issue is still there but I can live with it for getting a quality reel for basically half off. Thanks for the tips everyone, might try and solve the thumb bar issue if I can figure out what to do.

Today using my SLX in early morning. The reel and my hand got really wet and I had kind of same problem with “thumb bar struck” many times. I had to manually push the thumb bar back in place. BTW, The k and SLX use the same style thumb bar. The difference is I don’t have problem, when playing around or when my hand dry.
I will have to open it up to see what is going on, but my first impression is, the thumb bar on SLX is really in high position, when my thumb on spool, part of my finger is right on top on thumb bar. The second thought is spring might not be strong enough to push the thumb bar back in place even with light pressure. I might be wrong though, I hardly have this problem with all my Shimanos, but a few times with old Daiwa pixy.

On 11/7/2021 at 2:50 PM, Bass_Fishing_Socal said:

The second thought is spring might not be strong enough to push the thumb bar back in place even with light pressure.

This is the impression that I am getting from my reel. If you just keep your thumb away from the bar when engaging, it works perfectly.