i've been using the same oil mix for years without a real problem of carbon build up on the screens. I have redmax, echo, and Husky 2 strokes. i recently bought a remax blower, 4401, and a redmax trimmer, the tr123 i believe. they are about a month old now, and already i have to clean the screens. is it my ratio mixture? or do they burn fuel differently when they are still new? or maybe the screens are meshed smaller? my other redmax blower is about 8 years old and i don't ever recall having to clean the screen on it. any advice?