Ah, OK. Please look down the hole and check the disk at the bottom, it should be black, if it is stainless steel or white adding a black disk will solve it. Also check the propeller, I know the shaft is the black graphite reinforced one but we made this change before we made the prop tight fitting. If you try to twist the prop on the one I sent you it will be tight on the shaft, the other one should be the same way.