I was setting up the throttle linkages in my dads hobbistar 60, and all was going well. The carb at the time was very smooth. I had to leave the plane for a day, and when I came back, the carb was extremely hard to move, but it didn't feel like anything was in there. It also was just sitting in my garage the whole time, so nothing relly could have gotten into it. At first I thought it was a problem with the linkage because the pushrod was bending when the servo moved. I removed all of the linkage and the carb, and it was still extremely sticky feeling. I don't know rotary carbs very well, so I'm a bit afraid to take it all apart, but it felt like it was maybe binding in the part where the external arm turns on to move the internals. Any help would be appreciated, thanks.

The first thing I'd try before disassembly is to put a few drops of fuel in the barrel and see if that loosens it up. If not, remove the carb and submerge it in fuel for a while. If that doesn't do it, then it's time to disassemble.

Alright, it's soaking as we speak. This engine has never been run, and also, it was sitting in a hot and humid garage. Could that have anything to do with it? I'm really confused because I've never had anything like this happen to my RC cars. It's almost impossible to move with the arm.

If this is a recently acquired new motor then consider taking the engine or at least the carb back to the LHS (assumption there) and see if they will exchange/repair under warranty. It wouldn't take much in the carb to foul it.

If you take out the throttle stop screw on top (with spring), the rotating piece should slide right out. Take a look at the barrel and the carb barrel bore for any burrs or foreign objects.

Soaking it did nothing, so I took it all apart, and it was clean. Though I did drench everything in motor spray then after run oil just to be safe. I put it back together, and it was suprisingly smooth. Probably smoother and more consistant than when it was purchased. So I don't know what happened, but it works great now. Thanks for all who replied.