ORIGINAL: opjose
Also the Evolutions initially are prone to create a grey "goo" that will clog up the muffler pressure fitting.
The grey goo is material from the rear casing being initially worn away. This will stop as the engine breaks in.
However check the nipple often and clear it of debris, especially over your first season.
I have about 15 runs on my Evolution .61 and it still has a tiny bit of gray in the exhaust residue, but not nearly what it was when new. Its also taken about that long to break in to the point where I have a consistent setting on the low-end mixture. The more I run this engine the better and stronger is seems to run. I'm quite happy with mine.
The pins on the needle valves can be removed with nose pliers by pulling them straight up. The blue ring on the low-end needle valve can be removed also. I haven't had any issues with the blue ring on the high-end needle valve since I haven't had to lean the engine to that point.
Hogflyer