2012 250 Sport XS

[Steve Melton]

I bought my Allison used and didn't get the manual for the motor and was wanting to know what octane does Mercury recommend?

 

[JWolff]

2012 is regular unleaded (87 octane). The early 250's like mine that came out of the Mercury Racing shop were high octane (91 or better) but that was just the 2003-2005 I believe. Once they left the racing shop and into standard production they went down on the octane requirement but also lost something like 10 hp vs the early models with high octane.

 

[GotMyAlly]

Manual also states to bump up to 89 if it's running rough.

 

[Tim Powell]

03-05 91 min
06+ 87