Old water pump not compatible with new lower unit and driveshaft?

[Canadianwalleye]

Hi everyone. I just purchased a new lower unit for my 1978 Evinrude 115hp model number is 115899c
We’ve got the drive shaft in place in the lower unit but now we are at the point to reinstall the water pump but there isn’t a place for the key. Was I supposed to get a new water pump kit from sei in order to convert my old unit to new ? I was told all I needed was a new driveshaft... please help. I can’t figure out how the water pump mates with this drive shaft!! HELP!!!
Thanks everyone.

[Guest]

Your water pump is not compatible with our SE304 as it uses a different style key.

The water pump kit you would need to order from us is part # 96-306-01K.

I'm sorry if we didn't catch that at the time of the sale.

Please refer to the email we sent you over the weekend.

Best Regards,

Tech Support