I have always ran hight octane fuel in my two stroke, but I have been running in to more and more people that have just been using regular unleaded fuel.

Is it just because of the price?

Its all about money!

No, on a standard compression 2 stroke premium fuel will NOT help at all and very well can do damage...why???

Premium fuel is loaded with detergents (clean your engine ads) TCW 3 two stroke oil is also loaded with detergents. Mix the two together and you get the very real scenario of way too much isn't a good thing. Too much detergent breaks up the oil film properties, and the ability of the oil to do it's proper job on your rods, cranks and other moving parts is lessened.

I agree. Not going to argue the point but I get asked this question by boat owners a lot and the question allways comes down to: regular shure is a lot cheaper.

Ditto here. The "today" engines are low compression style and have been built to run on the low octane fuels. Contrary to some peoples belief, you won't get better mileage by running a higher octane nor will it start better. On the older V-4 and V-6 johnson/evinrudes, it will however, have a less "sneezeing" problem. But for the cost difference between grades, it ain't worth it. And no, it doesn't give you better preformance or higher top end speed....Myth Busters!!!!

I run 93 Octane.... But I have 155 PSI on all 6 cylinders.

I recently learned that higher octane gasoline has a lower energy content. High compression ratio more than makes up for it in hi performance engines. And boosting the octane in a computer-controlled engine with knock sensors yields more power because the spark timing can be advanced further.

Otherwise if your motor is designed for 87 octane, higher grades mean you're just paying more for less.

I too run about 150 PSI on a 1985 Merc and run premium. I am beginning to wonder if it is necessary. I researched octane boosters long ago but they work out to be more expensive.

It's my understanding that "compression ratio" is what counts -- roughly the volume inside the combustion chamber at 180� BTDC, to the volume at 0� top dead center -- instead of cylinder pressure. No idea why, though.

Apparently engines with compression ratios much higher than 8:1 or so will need premium gas.

The only purpose of octane is to prevent preignition.

I run what Mercury says to run. In my case, 91 minimum octane.

My Yamaha says to use 87 but it is a few years old. The dealership said the premium was too strong and it could cause motor damage.

An engine makes the most power it can, on the lowest octane fuel it can burn without detonation. The purpose of octane is not to make more power, but to lessen fuel detonation inside the combustion chamber. Anything running 10 to 1 or less, can happily run on all levels of pump gas.

the more fuel cost , the better it runs ???
or did I miss sumpin ???
lol

have a less "sneezeing" problem what does this mean???