I believe I left off Diesel engines that I did NOT use starting fluid on... sorry for the double negative that can be confusing.
Yes I use it on Diesel engines and when I need to have it run for a minute or longer (like when changing the fuel filter on a Cat engine) I'll use gas on a rag over the intake. On a cold morning a one second spray will save wear and tear on the starter. On a warm day that could be too much.
OP, with the key on see if you can move the rod on the fuel solenoid further into it. If it then starts you need a new one as they are known to fail.