How to change oil on my 1997 Mercury 40hp 2-stroke?

bassin_louisiana

Seaman Apprentice
Joined
Sep 17, 2017
Messages
46
Hi folks, I?m fairly new to outboard maintenance. The oil level on my 1997 Mercury 2-stroke 40hp is low and I need to add oil. I recently had the lower unit oil changed so that should be fine. My question is: do I simply pour the oil in the top or do I have to drain the old first? From what I understand, this is an oil injected outboard. Also, do I need to change an oil filter when I add new oil? Any advice on adding new oil, draining old, the process, etc. would be much appreciated. Thanks!
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Open the tank, fill it with TCW3 2 stroke oil, put the lid back on, go boating.
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,286
As ondarvar says....unless you have any doubts about the oil quality or water content. If you NEED to change it....you can get it out using syphon hose or pump. Filter (if it has one) shouldn't ever really be dirty. Usually inspect and clean and off you go.
Not a common thing to have to change the oil unless there is any doubt about it.
A good TCw3 is all you need.
All the best.
 
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