regular or supreme gas????

[hfd12]

i have a 1974 mercury 65 hp outboard and was wondering if u can use the high gas in her or just the regular gas with the oli of course. what ratio shoul i use also? 50:1? Is a little smoke comming out of the exhaust port normal? thanks

 

[hoytvectrix]

Re: regular or supreme gas????

I always run the higher octane gas through my motors. It gives a cleaner burn and i would assume you would also get a longer life outta the engine

 

[RicMic]

Re: regular or supreme gas????

"Supreme" isn't any more supreme than regular, its just meant for higher performance engines, if you engine dosn't require the higher octane(read manual)then you are just wasting your money, it actually burns LESS clean, if your engine dosn't require it and it WON'T make your engine last longer. Go by the manual on what OCTANE they recommend for your engine. The only time I would spend more than for the minmum recommended octane was if I could get gas without the ethanol in it.

 

[Alumarine]

Re: regular or supreme gas????

"Supreme" isn't any more supreme than regular, its just meant for higher performance engines, if you engine dosn't require the higher octane(read manual)then you are just wasting your money, it actually burns LESS clean, if your engine dosn't require it and it WON'T make your engine last longer. Go by the manual on what OCTANE they recommend for your engine. The only time I would spend more than for the minmum recommended octane was if I could get gas without the ethanol in it.

Yep, what he said.

 

[sschefer]

Re: regular or supreme gas????

I don't have a copy of it, FB or achris might but Merc issued a Service Bulletin no long ago stating that dealers should notify their customers to run 89 instead of 87 octane fuels as per the Owners Manual. You don't have to fork out the bucks for 91 octane but you should use at least 89 now.

I run 91-93 in all my motors but that's just me and I tend to push my motors.