The 2000 model, Mercury 25 hp outboard, requires a minimum octane 89 rated, unleaded fuel, however, with the quality of gasoline being what is presently, it would not hurt to run the higher octane fuels.
" regular " unleaded - 87 octane
According to the 2000 Mercury Sable Owner Guide : For the 3.0 litre " Vulcan " and " Duratec " V6 engines ( " regular " unleaded gasoline , 87 octane )
5w-30 is what I use in my 2000 grand marquis, in 2001 ford started saying 5w-20.
unleaded
" regular " unleaded - 87 octane
yes
For a 2005 Mercury Grand Marquis : " regular " unleaded , 87 octane According to the Owner Guide
you can use 87 octane reg unleaded or 97 super unleaded its up to you id go with what the pervious owner used
regular unleaded - 87 octane
For a 1991 Mercury Grand Marquis : " regular " unleaded gasoline , 87 octane is used for both the 5.0 and 5.8
" regular " unleaded , 87 octane
" regular " unleaded , 87 octane