http://www.rcuniverse.com/forum/m_90...tm.htm#9070204
If this is the problem you were dealing you didn't need any JB weld. A center punch should have been used to "peen" the ring back onto the throttle arm. The arm should have been replaced and then the punch use in the old punch areas to spread the metal out to hold throttle arm on. While not the best way to attach a throttle arm it is still a good way of doing, and allows for easily taking off the throttle arm if the carb needs to be disassembled for whatever reason. Unfortunately now your "fix" is permenant and you will never be able to get the carb apart if you need to do anything to it.

I'm not trying to be harsh here, but rather just trying to point out there the proper way it should have been done. Unfortunately it won't help you on this application, but the knowledge can help you for the next time you have to deal with something like this.