advice about gas

i was wondering if it is alright to run high octane gas in my boat, such as 93 octane premium? will it hurt it? is the octane too high because ive heard that the higher the octane the hotter it burns and it could burn a hole in the piston. anyone that could comment on this i would appreciate it.

Re: advice about gas

First, what is your engine? You should run the lowest octane you can without pinging. There is not a single reason to use higher octane than you need. It's not going to burn hot enough to cause any problems, but it will cause increased carbon buildup, as well as decreasing the weight of your wallet.

Re: advice about gas

Paul - You need to run the grade of octane specified by the manufacturer of your motor. For most outboards this is 87 octane but check your manual & if you don't have one - - - -. It is not good for your motor to run a higher octane than specified.

Re: advice about gas

I would follow the advice of the others, however you seem to want the best performance you can get from your outboard, so I will tell you about a product I have tested and am using with the results the manufacture claims. I do not sell this product and gain nothing from telling you about it. I am not the kind of guy that just throws anything off the shelf into one of my vehicles, but I can really tell the difference using this product, There is nothing in it that can cause damage of any kind to your engine. Read the link below and decide for yourself if you want to try it. I beleive however that you will like it if you try it, I will allways use it from now on. Engine runs smoother, starts easier, and the exhaust is noticably cleaner.<br /><br /> GTA Fuel Enhancer

Re: advice about gas

Actually, it's illegal to sell a motor in the US of A that will not run on Regelar 87 octane gasoline. What happens is that you have the regular grade gas. Then they squirt in the "octane" additive that retards the burn, so it don't ping. Then you got 89 octane. Then they put some more in & presto, you got 91 octane. You see each time they put this non-combustable additive in you displace that amout of gasoline. Therefor the "regular" grade has more energy in it than the "premium" grades. I know it's hard to beleive but if you use common sense, it makes perfect sense. Think about it for a second or two. If you think Chevron or Union or whatever your favorite brand is, is superior, you better follow a gas tanker sometime to see where they get their gas. They all get it from the same refinery. Gas is gas. They just squirt in their own "special additives" to bring it up to the same octane rating & you think your getting something special. Not.

Re: advice about gas

Originally posted by BinLurkin:<br />Actually, it's illegal to sell a motor in the US of A that will not run on Regelar 87 octane gasoline.

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Umm...no. There are lots of motors that only run on premium - the new Mercury Verado being one of them. Lots of cars (2004) models also require premium. There's nothing illegal about it. Also, for all you know this guy could have a very old or high performance motor...

Re: advice about gas

I don't want to argue who is right here. However this is what I was taught in school. This is back when I was into racing cars instead of fishing and boating.<br /><br />BinLurkin you are sort of right except what you are describing as octane to limit pinging is actually lead additive. Lead was introduced to get the gas to burn evenly in the combustion chamber. This is what helped aid in reducing the pinging.<br /><br />The octane rating is for the amount of compression ratio the engine has. The higher the compression ratio, the higher the octane is needed to prevent the pinging. Also the higher octane/compression equals higher performance.<br /><br />Look in a motor manual for the 70's model engines. You will notice that the compression rates were lowed when the unleaded fuel was introduced. The engineers found that lowering the compression that a engine could run without pinging on the unleaded fuel plus better emissions.<br /><br />So in short, octane ratings are for different compression ratios of engines. The higher the performance, the higher the octane.<br /><br />Running high octane in a low compression engine WILL burn pistons and valves. I know, been there and done that. That is why boating and fishing is a cheaper hobby to me. <br /><br />As for 2 stroke outboards, I'm not sure if this rule applies. It would be best to ask someone who races outboards for that information.

Re: advice about gas

My 1986 OMC 3.0 I/O specifies 89 octane and read on this forum that I can damage my engine with 87 octane fuel. 87 octane does cause my engine to ping a little.<br /><br />Premium fuel 91-93 octane truly feels smoother in just about any car I have ever driven ...especially in older cars with high mileage engines and also when pulling a heavy trailer in hill country. All these cars were rated for a minumum octane of 87.<br /><br />I have also seen improved gas mileage with premium. Not just imagined...it's difficult to imagine almost 100 kms (60 miles) more a on a tank of gas.<br /><br />I can also clearly see much cleaner spark plugs from only running a few tanks of premium. (probably from a higher concentration of cleaners in premium.)<br /><br />I suppose it's easy to see why many folks think premium is a hotter fuel from similar experiences others have had.