In my spares kit I have an impeller with a setscrew. My pump has a keyway type impeller. Did a search online and wound up even more confused. Looks like people are mixing up part numbers on these 2 impellers. I can find both type listed with the same part no. even though they are definitely not interchangeable. Can someone tell me the part no. for the keyway model? So I don't have to buy the wrong one like the previous owner did.