So Powerboat reports that the Merc 850SCI will get 100 less horsepower using 87 octane gas over 92.

What will happen if I use 92 in my 525EFI? Is a SC thing? Is it only the 850? What is the reasoning behind this. Forgive me for my ignorance.

I would assume it compensates for the lack of octane/presence of detonation by backing out the boost/timing since it has the feature that makes a constant HP output possible, that same idea will let it run on lower octane at a reduced HP... i would assume the 1075 does the same thing.... aren't computers great

The new 600SC will always make 600 hp regardless of temp or altitude. It is actually a 700hp engine so it can reach into its power reserve to maintain 600hp no matter what the conditions. I believe the 850 works the same way.

The 1075 doesn't do the same thing, because Merc doesn't recomend using anything but Hight test. What Merc is saying is that if you had to run 87, you can, with the 850! But the engine will compensate! Protect itself from predetonation! And YES, computers are great that way!!

I don't know if Merc will say this on any other high test fuel engine?

I was told that the Merc 600 is NOT making 600 HP.

i think the problem with the 600 is not the 600 but the 525 making more than 525.... little brother is a little too close to big brother right now, hopefully they will turn it up when a new drive is available...

I was told running the high test in the 525 only increases mileage. I run the good stuff and all in all the 525 isnt too bad of a gas guzzler.

Go to the Formual postings. Magicfloat (Nelems Marine) has a new 353 Formula with 600's going 96 mph with a full tank of gas on flat water (GPS). I don't think the 525's got anywhere close.

You might have gotten a bad tank of info. I got my info direct from Merc Racing at X-Site.

I don't know about mileage in numbers but I have 75 gallons and it seems I don't go through it too quickly. I will have to clock it a bit sometime.