Yanmar 4jht3 raw water pump leaks?

[Flod]

I suspect it's time to rebuild my water pump">raw water pump. I found signs of rust around the pump when changing the impeller. I can't see any drops or leakage but as you can see on the pictures the rust is likely to come from saltwater. Does anyone have experience of this operation and can give me some guidance on how to proceed? Thanks

[Lepke]

I don't know you pump, but if the leak is from the back you need a new - whatever seals the cover. Sometimes the cover becomes worn or distorted. All impeller pumps I know of have replacement covers, new gaskets or orings available.
If the leak is from the front, then it's the shaft seal. Once you learn how to replace it, it's easy. I change mine almost as often as the impeller, but don't change impellers as often as the rest of you. About every 5 years. I have 4 salt water pumps to maintain and don't find it a problem. I source my seals from bearing companies and pay about a tenth of the marine price. Good time to change the bearings, too.