# 01 Merc 25 2 stroke



## devrep (Feb 22, 2009)

So this is my new old motor. Did some googling around and read that some years they made the blocks out of Mercosil and that those motors should be run at a 40:1 oil ratio. Anything to this and what years would have had Mercosil blocks?


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## HaMm3r (Dec 11, 2006)

Supposedly, blocks with Mercosil had serial numbers G202750 and higher. My 1999 25hp was Mercosil so I'd bet your 2001 is too. Always ran 50:1 in it.


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## cutrunner (Jun 8, 2010)

A higher quality of oil will make more difference than a 10\1 difference in ratio


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## devrep (Feb 22, 2009)

Roger. Thanks.


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## RunningOnEmpty (Jun 20, 2015)

The older blocks used nikasil chrome plating on the bores. The Mercosil blocks started in 1994 If I remember correctly? I've owned both and always mixed the oil at 50:1 without any problems.


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