Oil loss in lower unit 1978 90 hp mercury

[Bchappy]

Drained lower unit for winter refill and found a cup or 2 left in lower unit. Refilled and now I am concerned about running this year though no evidence of shavings when draining. Thoughts ? I am planning to pull unit to install new water pump kit because it seemed to take 15 seconds or more to get a pee stream.

 

[Chris1956]

Re: Oil loss in lower unit 1978 90 hp mercury

OK, then replace the base of the water pump when you rebuild the impeller. The driveshaft seal is located in the WP base, and is is one of the most likely candidates for your issue. Clean up the driveshaft with sandpaper and oil it up before installing new WB base. Use new gaskets on the fill and drain plugs.