Dayton Salamander Heater - Blowing Unburnt Fuel/Smoke Randomly

Ok, got a Dayton 100K BTU salamander heater, ran great for a couple years. Nose cone got bright orange every time. After a while, the heater would be running fine, then the flame would go out and it would blow black smoke that smelled like straight up kerosene. This would be completely random. I took it in and they replaced EVERYTHING- the back cover, the air filter, fuel filter, lines, fan blades, spark plug. It ran a little better but was never cured. Well now it is worse than ever. It will blow smoke really bad, especially when you are kicking it on for the second time (still warm). Another thing to note, the nose cone is NEVER getting even remotely orange, and it is noticably not nearly as hot as it used to get. So I decided to try and troubleshoot... I took the cover off and ran the heater... ran great! Obviously not as much air was running into the combustion chamber, but it ran good and the nose cone even got about 1/3 orange! So then I start to put the top cover back on... halfway on it ran a little hotter... 3/4 the way on starts blowing smoke again. This would tell me TOO much air is getting pushed in? How is this possible? Ive tried messing with the screw adjustments on the back but nothing seems to change the issue. Any help would be appreciated since it has me and the local shop stumped.
-Brian