Kerosene is a lighter diesel oil than #2, hence why it is designated as #1 diesel. The lighter weight means it contains slightly less energy – about 135,000 BTU per gallon vs. 139,000 BTU for a gallon of #2. ... This is part of the reason kerosene burns drier, with less lubricity, than #2 diesel.
copied from the internet, i don't want anyone to get the idea i know what i am doing!