ui_fearmaite,

Some of the EVO 46 engines had issues even after redoing the needle valves and checking the "O" ring under the carb. [link=http://www.krcs748.com/evolution_engines.htm]Follow the instructions on this page[/link] and they will do whatever it takes to get it repaired for you.

I found that after mine would warm up it would go lean.

By accident I had flooded it and while trying to start it, it was spitting fuel out of the joint between the head and the cylinder sleeve just below the bottom of the head at the front of the engine, but this only happened after about 2 minutes of running on the ground. Evo repaired it and it has since been a very reliable engine (Runs as well as the 2 OS46AX engines I have)