Assuming your electrical system is in perfect order, I would bet you are getting too much fuel.

This could be caused by the following:

Float level off, or perhaps leaking. Heat up some water just prior to boiling, immerse the float, any bubble indicates a leak.

Leaking around the seat. Make sure you installed the gasket under the seat. Check for any cracks, or perhaps the old gasket is still underneath. An problem here would allow the gas to bypass the needle & seat.

Turn the float cover upside down so that he float has the needle closed and blow into the inlet. You shouldn't be able to blow through (using about 5 lbs).

Run thin wire through all of the small passages. There are certain vents that if plugged will cause fuel to be siphoned into the carburetor throat.

Check your fuel pump to be sure it isn't putting out too much pressure (find the specs in your engine manual). New fuel pumps are especially suspect. Electric fuel pumps need a regulator installed.

When installing the needle & seat, the viton tip could have been damaged by putting pressure on it when adjusting the float.

Sometimes wiping the needle viton tip with mineral spirits will help. Just wipe until you don't get any black on the towel.

Test the main discharge to make sure it is sealing when not in use. It could be siphoning gas here if it isn't sealing.

Jets are probably not the problem unless they are a lot oversized.

If you have the black Nitrophyl type of float, then be sure to replace it. They tend to absorb over time (years). Once they get too heavy, they will start to sink and let too much fuel in.