If you are 'drooling' fuel along the gun, your steam atomizing pressure might not be up to what it is supposed to be. If that is the case, raising it would help. If it is already where it is supposed to be, raising it will result in what I stated above.
If it is what it is supposed to be, check your steam piping to make sure it is trapped properly. You might be getting moisture in your steam and that isn't helpful.
Also, your gun tip pieces/parts might be worn out. Have you checked them lately? If the steam holes are gone or plugged, or oil passages are plugged or worn so that they are open more than designed, your gun will 'drool' (dribble) oil out the tip.
For an oil burner of any type, steam or mechanically atomized, the tip components need to be top notch and burning heavy oil is tough duty even on some of the hardest materials known to man.
rmw