Today had a bad day at the field, First flight The plane seemed to Just Die in the air, So i tuned her up and Once u hold her vertical she seemed to labour and loose power and gain power, when i tried to richen her up it just wouldnt work she then got too rich and bogged down so i couldnt find that happy spot, Then i Checked the fuel tank and lined and there are no air leaks, NO air bubbles in the lines at all, checked the glow plug and i found something in it so i changed it, and then after 2 more glow plugs they seem to be keeping something stuck in it, so i took the head off and this is what i found
do u think this is the reason why she wouldnt hold a tune??

I have Never seen so much carbon in my life...
the fuel im using is 20% oil
15% synthetic ( Klotz 200 )
5% castor ( Degummed racing Eguina oil )
and the rest methanol... Im using the best ingrediants.And i got no ideea where all this carbon came from..