Sulfer & water content....and if it's off road diesel fuel - the color. It won't cause problems to use diesel in a heating oil tank, but it will cause a whole lot of trouble if you use heating oil in a diesel tank
Difference is capacity and the fuel type.
#2 Fuel oil and #2 Diesel fuel are similar, however, the motor fuel will typically have lower sulfur content, and have additives to help with engine lubrication and cleanliness.
The difference between diesel fuel and gasoline is the amount of refining that occurs to the oil. There are many different "flavors" of oil that are pumped out of the ground in varying locations. Depending on the oil that is pumped out, it's easier to use the oil for various different purposes. Furthermore, oil is then refined in large facilities call oil refineries. Gasoline is more refined than diesel fuel, which is the main difference between the two, as far as I know.
What are we actually asking here? Lubricating oil? The generator should come with a note as to what lubricating oil it uses, and different diesel engines in cars and lorries require different grades of oil. Or are we asking about fuel? Generators can be run off Red or Agricultural diesel as there is no Road Fuel Duty to pay.
the difference between heating oil and diesel is a red dye, you can use diesel just fine
Deisel is made out of plants.
diesel is a fuel that has oil in it
No #4 diesel fuel oil is for oil burners and will not ignite in a diesel egine
There are not any calories in diesel fuel oil. Diesel fuel oil should not be consumed by humans or animals. Consumption of the fuel oil can be fatal.
The difference between the two is quit small. Normal diesel contains less oil than performance diesel. However, when they are tested side by side, no one can tell the difference of the two.
Diesel fuel is often referred to as "diesel oil" or "heavy oil". Do not confuse this with "engine oil for a diesel engine" which means "lubricating oil specially formulated for use in diesel engines". My first Ford Fiesta diesel's tax disc said - "Fuel - Heavy Oil". They've now realised that this term is anachronistic, and my latest tax disc reads "Fuel - Diesel". To be pedantic - Diesel fuel is an oil - Petrol is a spirit.
There are different grades of diesel fuel and heating oil but in general they have similar qualities including the flash point. The flash point is the temperature at which the fuel ignites on its own, without a spark. Diesel fuel used to only be available along truck routes. Before diesel fuel became easily available everywhere, people with diesel engine cars would use heating fuel, but would have to make sure it is clean, passing it through a filter to remove foreign particles.