There should be a white nylon screw on the side that will adjust the size of the coin it will accept (within reason, but well within the differences between a US and Canadian quarter). I would first try adjusting that screw until coin is accepted. I don't have the mech in front of me right now, so I can't give you any detail beyond that, but I can take a look tonight to see if there are any other adjustment areas.
Hi Mike.
A friend and I experimented yesterday with US quarters, Canadian quarters, and tokens.
We did adjust the white screw that you mention (diameter regulation), and that helped but.........the other variable was the magnets. We tried removing them, reversing them, and multiple combinations (one side on each magnet is blue, and whether that means something or not, we don't know).
At best, we could get the US quarters and tokens to accept. We could not get the Canadians to work, no matter what we did.
Sometimes they would jam in the mech, and at other times, they would reject.