While you have the lower unit seperated from the upper, there is a O-ring that is in there, next to the water pump housing for the gear lube. It is under $2.00 and is worth replacing.
Don, The Mercruiser diagrams I am looking at Do not show a gasket between the gear housing and driveshaft housing....
It's commonly called a quad ring, and it's included in Impeller kit #47-43026K06 as does the tool for the face seal. But, It does not include the gasket and orings for installing the drive back onto the bellhousing.
Right. But I wouldn't be removing that to replace the impeller. ?