The gauge on my tank appears to be stuck. I'm assuming it's stuck since it's been a month since my last oil delivery and it is still reading 7/8ths full. Is replacing the gauge something I should try?
HO here, that worked for me with my Roth tank months back. the guess from techs was that fill went slightly past the recommended max, and some foam temporarily gummed the works. Company offered to replace the gauge, but on a hunch i tapped it and it went back up. (In my case it was stuck lower than should have been, leading me to think delivery amount was less than receipt said.) It's been fine since.
Note that on a 275 gal roth tank max fill is 263gal and recommended max fill is about 240gal; so I've been told by techs who should know.
What kind of tank do you have? Is it a Roth? If so you will need to get the same gauge as you have now. If you have a standard type 275 you could get the same gauge type or get the bobber type as I described.