25 Merc Block and Pistons

J

jonbo

Recruit
Joined
Nov 18, 2010
Messages
4
I have inheireted a basket case 1999 25 mercury, The s/n on the mid section does not match the s/n on the block,Is this normal? The s/n on the block is og021968(NO MERCOSIL STAMP), I see that there are two different types of cylinder material with different pistons and rings for them. I have a set of OEM pistons that I cleaned up and measured that are in good shape. My question is are these the correct pistons for this block? The block also measured out standard and in good shape. The casting #'s on these pistons are 767-9014a15.
 
Last edited:
Faztbullet

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,938
Re: 25 Merc Block and Pistons

The s/n on the mid section does not match the s/n on the block,Is this normal?
Click to expand...

Only if newer block was installed....
The s/n on the block is og021968(NO MERCOSIL STAMP),
Click to expand...

All 15/20/25 hp motors after 1994 went to the mercosil block, check block over really good as it cast onto block. If it does not have it embossed on block its a chrome bore and someone installed swapped the serial #'s.
 
J

jonbo

Recruit
Joined
Nov 18, 2010
Messages
4
Re: 25 Merc Block and Pistons

Thanks for the quick reply, there is just the casting # on the #1 cylinder. I have also another block that came in the basket that is mercosil so I am confident that this block is chrome. Do these pistons match for a chrome bore?
 
J

jonbo

Recruit
Joined
Nov 18, 2010
Messages
4
Re: 25 Merc Block and Pistons

Is there a s/n on the front end of the block so i can match up the block halves or does it matter?
 
You must log in or register to reply here.
Top