How to change lower unit oil on 1986 Mercury 25hp

[07m109r]

just got the boat and im sure it hasent been changed in forever, just curious how exactly its done...

Gas was varnish, had to change the plugs and fuel filter and took a long time to get it running decent.

 

[Dave1027]

Re: How to change lower unit oil on 1986 Mercury 25hp

Usually drain by removing all plugs. Then pump new oil in from bottom hole till it runs out top. You need an attachment on the oil pump that threads into the bottom hole. Put top plug(s) back in and then bottom. Done.