Reply To: Impeller drive pin/key

[foot_doctor]

Yup, the Mercury drive key is .125” in diameter. I make them from 1/8 inch stainless stock that I buy from McMaster-Carr. I don’t trust the impellers that have plastic cores. After long-term storage, the rubber vanes adhere to the pump housing, and when they are forced to rotate, the drive key simply carves a slot thru the plastic hub, and the pump fails. The brass hubs live a long time. They are robust enough that they can be used to rebuild them like Brian Wilcox does for us. Get the brass hub one. Your engine is worth the extra investment. R.T.