Fuel?

[CoachDePo2]

I recently had the carb rebuilt and some other minor work on my 1991 Cobalt 222 Conduere. I have a V8 7.4 Merc. It was recommended to use 90 octane fuel. Most places only carry 89 or 93. I just wondered what type of gas I should put in and/or any additive to use along with it. Thanks in advance!

 

[alldodge]

If its a Merc stock motor 87 is all that is needed, higher octane just drains the wallet faster

 

[tpenfield]

Aren't recommendations great If you are filling up at the gas station you could go with the 89. The 87 will still be fine. On the water, most marinas are 89.

 

[Scott Danforth]

I believe the recommendation is 90 octane RON or 87 octain R+M /2 method (average of RON and MON). when boating outside the US you will find more of the RON measurement of octane. in the US the standard is R+M /2 method

so 87 octane.

 

[444]

I like to keep the ethanol fuel out of carbed engines that sit for long periods, in that case if I would have to run 91+ to find anything without ethanol, however I would agree that you will be fine on 87.

 

[TyeeMan]

And always treat the fuel with a quality stabilizer.

Oh boy, here comes the debate. . op2::ranger:

 

[alldodge]

And always treat the fuel with a quality stabilizer.

Oh boy, here comes the debate. . op2::ranger:

Right up there with Seafoam

 

[TyeeMan]

Well, in all honesty I'm a firm believer in fuel stabilzer, , snake oil or not. Why, because I've always used "it " and it works for me. Do I have proof otherwise? Nope.

I'm sure further comments will ensue.