Pipe connections not fitting correctly

[wstalcup]

Hello,
My Jandy pool pump died and bought a replacement pump (a Hayward pump)
The new pump connects to 2" pipe and my current pool pipes are also 2" but they are a little off
The old nut on the pipe is just a little to small to screw into the new pump. Also the new connector that came with the new pump doesn't fit onto the existing pipe. The existing pipe is just a little too big. There is some wording on the existing pipe but it worn off a bit. It seems to say things like PVC-DMV F-480 D-2665.. I believe the company that installed the pool may have used non-standard pipes. I don't know how this pool company was.. Anyway, any suggestions? The only thing I can think of is to cut off the existing nut and connector and sand down the pipe a little to allow the new connector to fit on. any other ideas?
Thanking in advance!

[Teapot]

Hayward are often metric pipe sizes 63mm which is larger than 2" (around 61mm) some use buttress threads others 55-60degree.
Can you be a little more specific?

[Denniswiseman]

I agree with Teapot the pump unions may be metric
Where are you located
What does the spec for the new pump unions say, they often have an adaptor
I wouldn't sand down a pipe to fit, get an adapter