What is this part? Carb bushing?
 

Ok, so the car sat for 2 years so I was draining the gas and cleaning the carb when I went to shake a jet out of the top and this little bugger fell out onto the bench. I have no idea where it came from. The only place that I thought it might fit would be under the accelerator jet but the piece makes no sense. I started the car without it in the carb and seemed to run fine... But I'm betting if mazda put it in there, it must do something. That pin sized hole doesn't look stock but it goes all the way through.

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Looks like one of the little weights that go in the carb, but if it was under the jet, it was in the wrong place...

It did not come from under a jet. It fell out of somewhere while I was shaking a jet out. I didn't see where it came from. I was holding the carb in my hand so I am fairly confident it came from the carb... Can you be a bit more specific on where the "weight" is supposed to be?

Check ball weight, looks like. Part of the accelerator pump circuit, it's supposed to sit on top of the accel pump outlet check ball to make it close better.

There should have been a small check ball under it, too - though sometimes they get stuck from dried fuel varnish.

Exactly where it goes depends on your version of the carb (some carbs have two) but it probably came from under the accel pump outlets.

Don't believe I've ever seen one with a hole in it, though.

I betcha someone drilled that to create an anti-siphon effect, probably due to an accel pump that was drawing fuel out at sustained high revs. It's similar to a problem experienced by Holley users. I doubt this mod worked very well but who knows. He should have looked elsewhere in the carb to solve his problem such as making sure both checkballs and both brass weights are there.

By the way, I think all Nikkis had them, not just some models.

Was of the impression that some models had one, others two, but that's an old memory and by no means reliable.

I know mine has two weights; a large one and a small thin one.

Edit: I checked, looks like all Nikkis have two, Power Valve Inlet (small) and Power Valve Outlet (large).

The one in the OP's pic is the large one, for under the outlet jets.

thanks guys for the response. This actually seems pretty helpful. I didn't see a ball valve under but the carb kit came with a few ball bearings. I'm hoping there isn't that big of a difference between them. I would like to find the second weight so I know it is there also.

This is on a IT7 car so I'm at high rpms all the time, so the hole makes sense.

I have personal experience with the check ball getting stuck at the bottom of the bore due to fuel deposits. Solution was to use a magnetized ice pick to gently work it loose.

You could use compressed air at the other end of the channel... but the ball may end up shooting the cat in the yard.

And thats bad how?

Ask the cat.