Spark plug colour

I think you should do your plug chop at 5100 just use your brakes. But yes those look too rich.

Thanks. I’ll have to tie the tail down to do a plug chop at that rpm or she’ll tip on her nose! I was thinking she might be running too cold. My CHT runs at 80°c and oil is at 90°c (both at bottom of green) and sometimes even lower as it is winter here at the moment. I have taken the summer cowl flaps off which will increase temps. Thought I’d start with the easy stuff first.

these are my temps. The farthest right is with summer cowl flaps on. Middle is winter cowl flaps on. The left is before I did any cooling improvements. This picture was taken in summer.

I would say if I run with the winter cowl flaps at the present season here, my temps would look something like the right picture, which is much warmer than I get at present  

I would like to have  the specialists opinion but for me, regarding to the temps you are good because all temps are in the green arc.

In my understanding if your temps are in the green arc everything is OK.

Unfortunately CHT and Oil temps do not tell much about mixture. The CHT was a great thing to have when we had air cooled engines, with water cooled heads, does not mean much. Oil temps say more about your cooling system and radiator/oil cooler flow than mixture.

The key temp for mixture is EGT, this will go up quickly as you lean off the engine the range is in the Rotax manual. There are others on the forum more experienced than me, but I would drop the needle one notch and see how the aircraft performs and the plugs look. Different fuels burn differently but again those appear rich.

My next move will be check the needle and maybe lean a notch