Throttle arm popped off
 

It is not broken just popped off, as you can see in the 2nd photo the arm does pop right back on.

Besides the obvious solution of welding, which I don't wanna pay someone to do, will 30-minute epoxy or JB Weld epoxy be strong and heat resistant enough for a permanent fix?

RE: Throttle arm popped off
 

G'day Mate,
I would take the throttle part off the throttle barrel, It's usually held on with a small "allen screw", support it on a vice or table, slip the throttle arm back on, & peen the riveted sections, with a small punch.
Do it carefully, & it will be better than new.

RE: Throttle arm popped off
 

I had exactly that problem with a Kangke SK.50 engine. The arm was held on with four little pressed/swaged dots. I had to fly at 3/4 throttle until the fuel ran out.

JB Weld did fix it, but eventually I swapped the carb for a Perry anyway and never looked back.

RE: Throttle arm popped off
 

I had the same thing happen with an OS 70FS, as Alan mentioned, you can remove it then peen it back on but JB Weld after that is a good idea. I just bought a new one for a couple bucks at my LHS. That doesn't happen often but it happens enough for my LHS to stock them.