Although it is very close, #2 home heating oil is not the same as #2 diesel oil. It only has the same lubricating ability and ignition quality. Refiners don’t intend home oil to be used in internal combustion engines. Fuel that’s made to be burned in a furnace might not have the same ignition accelerators, smoke suppressants and biocides to kill bacteria and fungi that are usually present in diesel fuel – the ones that vehicles use.
If you use home heating oil in a generator, you could cause serious damage because it will void the manufacturer’s warranty. Some of the first issues you will encounter are damaged fuel injectors, fuel pumps and engine glazers. Fuel companies would advertise it if heating oil was okay to use in compression engines, but they don’t, and for good reason.
A generator needs specific additives that home heating oil doesn’t have. So, if you are using it, it’s a sure-fire way to cut the life of fuel injectors, the injector pump and other components. As already mentioned, the warranty will be void because failure is not due to a manufacturing defect.
Remember, diesel oil is thicker, and as such, it has more lubricating properties. It gels better in cold weather, which makes starting more difficult, and it can also cause rough running in engines it’s not designed for.