Greg,

I have never seen a fuel pump force a needle off the seat but Jon indicates it can be done. It's real simple to pull the top off the carburetor and pull the float off and take a look at the needle. Any modern needle would probably have a Viton tip and it should appear intact. You can drop the float into a little pan of fuel and make sure it floats.

Use a flashlight and look up into the seat. If you see any bug legs or pieces of wood jammed in it, you have found your problem. Reassemble it blow into it while holding the float up. It should seal completely.

I wouldn't condemn the fuel pump if the replacement carburetor wasn't known to be perfect in the beginning. It isn't unheard of to replace a defective item with another defective item that was in a box in the corner.

Stuart