2002 TXTG knock issue

[Mwood]

I have been working on a 2002 EZ-GO that the oil was ran out of it last year.
I was able to brake the motor loose to get it running again. But not without breaking the flywheel. I shopped around and found a used one. When comparing the two fly wheels I noticed that the key is in a different location on the newer one.
It ran with this arrangement but the motor locked back up in a couple of months.
So I sent the motor out for repair. when I got it back in it just didn't seem right. I called the rebuilder he assured me that it was running fine.
I let the owner run it and after some 30 round's when he was complaining that it is knocking and taking oil. I called the rebuilder and he thought it was the clutch. I took it apart and it seems fine.
I am wondering if the difference in the fly wheels that is doing it.
not sure where to turn