2004 496 HO Octane question?

[cherry82482]

Hello everyone,

I currently run 93 Ron octane in my 496 HO. I want to know if I can run 89 Ron octane according to mercruiser marine? It would be nice to save a little cash at the pump. :)

[blackhawk]

Hello everyone,

I currently run 93 Ron octane in my 496 HO. I want to know if I can run 89 Ron octane according to mercruiser marine? It would be nice to save a little cash at the pump. :)

Actually that motor is designed for 87.

[ragbagger270]

The higher compression engines don't like the ethenol laden fuel at most stations. Always causes the need to run a grade or two higher. Starbright makes an excellent additive to stabilize the effects of ethenol.

[cherry82482]

Thanks for the tip. I just did the research and you answered my question. I will now run 87 octane. Maybe I should use some common sense.

[BlownCrewCab]

If it's a computer controlled engine, the computer adds timing until it senses knock and then pulls back a few degrees. The better the fuel the more timing it can support, end result is a tad better performance with the higher octane.

[blackhawk]

If it's a computer controlled engine, the computer adds timing until it senses knock and then pulls back a few degrees. The better the fuel the more timing it can support, end result is a tad better performance with the higher octane.

The computer will retard timing if a knock is detected. But there shouldn't be any knocks with GOOD 87 octane fuel.

[MOP]

With the lower octane you may gain a bit of power!

[fasttrucker]

Use 89,mid-grade.The 87# will go down with time.So to be safe go with the mid-grade.