If you can get help at a local field, do it!

As has been mentioned, DO NOT run an ABC engine rich! You will wear it to the point of no compression fairly quickly.

You should lean it to a decent 2 cycle run, not breaking into a 4 cycle, but only for 3 to 4 minutes (full throttle), then it needs to be shut down and allowed to cool completely. Repeat this through 3 - 4 tanks.

You want the 2 cycle run to get this engine up to normal operating temperature, let it run there for a couple minutes, then shut it down and allow it to cool (enough so that you can comfortably put your hand on it). Repeat.

An ABC (or ABN) engine has a tight piston to sleeve fit (often nearly too tight to turn over when new). The sleeve expands more quickly when heated resulting in lower (operating) compression. Running rich prevents the sleeve from expanding, and piston against sleeve friction wears the sleeve out quickly. The result is very little compression. (Bad for any engine.)
Dennis-