cleanout plug size help

[juicebox]

In our parking lot we hace a threaded cleanout that needs a plug. the actual id is 2.5 inches. a 2.5" plugs actual od is 2.75 and a 2" is actually 2 5/16". does anyone know of a threaded plug that is actually 2.5 inches?

 

[Mr_David]

Very odd !
if you dug down about 6", how is the fitting attached to the pipe?
Is there a banded coupling? might be easier to just replace the fitting.