Would like to find out what kind and grade of gas most of you use in your boats

I have always just run the regular low octane in my smaller two strokes.I have tried premium but what I found was that clean and moisture free was the key.

I always use the middle octane (89), on the advice of my boat mechanic. I run both a 115hp two stroke and a 9.9hp four stroke off the same tank (through a water seperator and check valves).

I think the important thing is that you use a fuel stabilizer, something like OMC 4+2. I'm told fuel can lose its octane and becomes "stale" within a matter of a month or two if you don't use the stabilizer... something that could easily happen in your boat's tank over course of the winter.

I also always fill up (got a 35gal built-in tank) after every trip, this is something I learned from flying airplanes. If you leave airspace in your tanks, you're just inviting condensation buildup, which results in water in your fuel... so keep your tanks full of fuel, and you get much less condensation. On airplanes, there is a fuel sump drain that you drain off and test before every flight, to see if there's water in your fuel. I haven't yet seen a boat with this feature. :-)

Oh, and another important thing, don't buy cheap gas. Cheap gas (ie. Safeway, Costco, Arco, etc.) has a high alcohol content. You don't want alcohol in your fuel. Alcohol attracts water, and it also eats away at the rubber components in your fuel system, like all the o-rings and hoses. Spend the few extra pennies per gallon and buy quality, non-alcohol fuel, from dealers like Chevron or Texaco.

-N.

RIGHT ON StorminN!!

On advice from my mechanic,I only use Premium fuel and good oil.If you need to save a few bucks,drink cheap beer.
I run a 140HP main and 8HP kicker on a 16' Glasply.Both Johnson.
The higher octane of Premium gas and the high quality oil helps prevent coking in the cylinders.That will kill your motor.
I tried some oil that was pricey(Quicksilver) thinking that meant quality.Not neccesarily so.Smokey..Smokey and foulin' my plugs.I went back to Johnson oil.

If you try to go cheap,it will bite you some day.

I believe Boater's World will only insure motors that use only Texaco or Cheveron.

Even if I have to completely fill the 50 gal. tank (normally I just top off at end of day) on my 19' Glasply, it only costs an extra $7.00 to use the premium grade gas. Well worth the price! Like the others said, use good quality (brand name) gas without the fuel line eating alcohol. Keep your tanks full to reduce condensation, plus you get on the water quicker then. If your boat doesn't get used over the winter, shut off or disconnect the fuel while the engine is running. Let the engine run 'til it quits. This drains the carburater and prevents the float from sticking or the rest getting gummed up. Use fuel stabilizer if your tank doesn't get fresh fuel for longer than about 3 weeks. Well, I got a little carried away, but 92 octane gas burns hotter, runs smoother, and doesn't carbon foul a motor nearly as bad as the lower grades. This is particularily true if you do a lot of trolling with the motor.

I forgot to mention that I buy my OMC two-cycle oil in bulk from my boat mechanic, it costs lots less that way. He sells refillable plastic can made for this... check with your mechanic, they might do the same.

Also, I use Mobil 1 synthetic oil on the four-stroke, it only takes 1qt, so who cares about paying a little more for that one quart? I think the motor will last longer with Mobil 1, also something I picked up from the airplanne world.

-N.

Definetely Chevron or Texaco (92 octane) for gas.

DO NOT USE 76 W/Pro Power. You will be hating life. That stuff is crapola.

For oil, I use Chevron oil in my 4 stroke. I have tried Mobil 1 synthetic oil also. Mobil 1 is suppose to be the sh** as far as motor oil goes.

My drift boat is usually powered with Coors and Gentleman Jack.

"Give a man a fish and he eats for a day, teach a man to fish and he will spend the rest of his life drinking beer in a boat"

Someone has to disagree, right?.

I totally agree with the no-alcohol and the good quality two-stroke oil arguements, but contrary to popular opinion, 92 octane fuel is not cleaner burning, hotter burning or more powerful. Octane levels refer to the fuel's point of spontaneous combustion. The higher the octane of a fuel, the less likely it is to ignite prematurely. This is important in engines with high compression ratios. In high compression automobiles, high octane gasoline is needed to prevent the gasoline from igniting prematurely in the combustion chamber. Your average automobile has compression ratios of 8-9 and runs just fine on 87 octane. High performance engines run compression ratios 9-10. Race cars run 10-14 and may need 100+ octane. Diesel engines need compression ratios of 20+ just to burn that dirty diesel fuel. MOST TWO-STROKE ENGINES RUN COMPRESSION RATIOS OF 6-7!!! High octane fuel won't make any difference(although the placebo effect can do wonders!) Four stroke outboards are a different story. Some of them are almost racing engines and may need high octane fuel.

Complicating matters: The octane ratings are composed of 2 components, research octane and motor octane (RXM/2) divided by 2. The research octane is the quality of the base stock, the motor octane is derived from additives. Problem is the highest octanes are achieved by motor octane additives, which may gum up the pistons in a 2 cycle engine. So some high octane fuels(from gas companies that use low quality additives) may well do more damage than good in your two-stroke.

What to do? Get out your engine manual and check its compression ratio. Unless it is over 8, don't waste your money(buy me a beer instead).

It is best you run the highest octane you can.The higher it is the cooler your engine runs.Lower octane fules burn much hotter by nature and when you run it inA high compression 2-stroke, You generate excessive heat and it will burn out your powerhead.The physics of it is,92 is the size of the OCTANE carbon chain. The more carbon in the chain the cooler it runs. Detonation comes from excessive engine temp. and A fuel that ignites at A lower temp. and yealds more heat. Think about what dragsters run or (av gas) for air planes. They all run the highest 0ctane possible

You are off on this one Dutchman. Gasoline molecules have between three and twelve carbons(mostly seven through eleven). 92 octane gasoline is a blend of the various size molecules that act(ignite) as if it were a blend consisting of 92% octane and 18% heptane. 87 = 87% octane and 13% heptane.

Problem in today's fuels is that the octane level is increased by using various additives. Some use alcohol to do this, others use MTBE.

What makes you say higher octane fuel runs cooler? There is no appreciable difference in the heat of combustion from 87 octane to 92 octane gasoline. If anything, I would expect higher octane gasoline to burn hotter. Funny cars run alcohol right? They run extremely hot. The temperature of your engine has a lot more to do with your ability to cool it than the fuel you use.