Tweaked with my older Hydrotek yesterday and put in a different fuel nozzle on the burner (went from 2.25 to a 2.5). Been reading some comments lately about super heat and oil emulsification so I wanted to test it out a little. With reduced flow and new nozzle I got 225 degrees out of the coil and I was pretty happy with the results on the gas station i cleaned last night. As I was ball valve rinsing some asphalt I realized I left the burner on and it was billowing black smoke. Today I start up the machine and I have a full blown smoke show for two hours, tons of soot from what I can see, and only able to achieve 125 degrees at full flow (175ish before). I think I drowned the coil and insulation in fuel. It was intermittently firing so I put the old 2.25 nozzle back on, new electrodes, checked for solid spark.....still billowing black smoke like crazy. I can see consistent flame, could the soot build-up be keeping my temp rise down 50 degrees? (only able to get 125 degrees)