Dear Bax,

Thanks for the reply, you have mentioned that I should open the throttle to full and immediately lean the engine so that it is running in 2-cycle mode ... problem is that I expect that the engine should be around 6000 to 8000 rpm for running in, but this engine does not want to run below 10,000 which I think is too high for break in????

If I try to bring it down from 10,000 by opening the needle at full throttle, it suddenly goes too rich and I have to kink the fuel line to keep it running ... closing the needle again beings it to around 10,000 suddenly ... This is my first experience with this type of a pumped engine so I do not know if this is normal behavior ...

Please also consider that where I am the current ambiant temperature is around 35degC. I am using #8 OS plug, and an OS pipe.

Any further suggestions?