For everybody in the grand rapids and lakeshore area, i found 87 octane recreation fuel with no ethenol at the torco station right next to pigion lake. I also stopped at the mobile in allendale and they also have recreational fuel but it is 93 octane, not recomended for most outboards i believe.
So how much is it a gallon???
BD ;D
Do NOT run premium gas in your outboard motors unless the manufacturer recommends it. It can actually cause damage because of the higher octane (a long explanation could follow but just take my word for it!)
Go ahead. Explain it. No one has posted that in quite a while. I bet there's some people on here who would like to know?
Forget the explanation how much is the recreational fuel??
I filled up about a month ago when gas prices were around 4 dollars and i believe i paid about 4.25. i usually use the rec gas in the spring when i dont use the boat as much and in the fall before i store it for the winter. In the summer when i use the boat frequently i use regular gas with additives to save money.
Quote from: Waterfoul on April 25, 2012, 07:30:36 PM
Do NOT run premium gas in your outboard motors unless the manufacturer recommends it. It can actually cause damage because of the higher octane (a long explanation could follow but just take my word for it!)
I'd be interested in hearing this explanation! I know no regular in high compression engines that require premium, but I've never heard no premium in a standard compression engine. Typically engines have minimum octane requirements and I've never heard of them having maximum.
If I stopped at a station with 93 octane and no ethanol, I would use it. Please tell me why I shouldn't.
Thanks
Please share explanation on Premium in outboards. I have been running premium rec gas in my Yamaha 60 hp 4 stroke since new 2 years ago just to get away from the ethanol issues. Motor only calls for 87 octane.
Premium rec gas is the only rec gas offered in my area. It is only rated 90 octane though. I think the ethanol when mixed does add octane to get a 93 octane e-10 premium pump gas
OK here it is to the best of my ability, as explained to me by my Merc. Master Mechanic friend:
Premium gas is higher octane. Higher octane has a higher flash point (meaning it takes more heat and pressure to make it go bang in the compression chamber). Because of this our outboards actually have to work harder to make the gas ignite. It will ignite further into the compression stroke, meaning it fires at the "wrong" time. In most engines requiring only 87 octane, you will actually get a power and performance loss running 90 octane or higher fuel, and you will use more fuel because the motor doesn't have time to burn all of it in the now shortened compression stroke. It throws the timing all out of whack. It can also cause premature wear on the reeds in the motor.
Conversely, engines requiring high octane that you try to run on lower octane have the same issues in reverse... they fire to early in the compression stroke... causing "pinging" and valve damage due to unburned fuel.
In the long run it will cost more to run premium fuel than it would to simply run the correct 87 octane fuel with a good ethanol treatment additive. The treatments are very concentrated, and most people actually put way too much in their fuel. If you read the directions on the bottle and follow them you should have no issues.
I hope this helps. Correct octane fuel, good ethanol treatment = years of fishing pleasure.
Mike
Waterfoul, was his explanation referring to Premium E10 or Premium rec gas or both? You already have a built-in power loss with the 10% ethanol gas.
Also is he referring to 4 strokes and/or 2 strokes and is he talking just about Outboards or all motors in general. Sorry for all the questions.
Quote from: bigmojet on April 26, 2012, 06:03:49 PM
Waterfoul, was his explanation referring to Premium E10 or Premium rec gas or both? You already have a built-in power loss with the 10% ethanol gas.
Also is he referring to 4 strokes and/or 2 strokes and is he talking just about Outboards or all motors in general. Sorry for all the questions.
It's not the ethanol that's in question... it's the octane and the flash point of the fuel. So to answer the first part, it doesn't matter. 93 is 93, 87 is 87. Yes, the ethanol does have an effect on the "power" that gasoline contains but you should be more concerned with the octane level. At least until they try to shove E15 down our fuel injectors. At that point I'm not sure what we will do. The boating industry, snowmobile industry, lawn machine industry, dirt bike manufacturers, and many others are trying to keep the E15 from reaching our gas stations.
And as far as I know it doesn't matter which motor you have... if it's recommended octane is 87, you should not be running 90+. It's no different than your car or truck. 93 (premium) octane fuel in a Chevy or Ford or Dodge pickup designed to run on 87 (regular) gas is just a waste of money and can in the long run, cause damage.
Waterfoul is right on the money. Higher octane gas is harder to ignite, to prevent detonation in higher compression motors.
The higher the compression ratio of a motor, the more heat is generated with each stroke of the piston. Parts of the piston can become hot enough in a high compression engine to ignite the air/fuel mixture before the spark plug fires. The process is known as "detonation". High octane gas requires higher combustion temps to ignite it, preventing the problem.
In an older distributor driven motor, this adds up to "free" horsepower. Changing to premium gas in my mustang allows me to advance the spark, increasing power. However, outboard electronic control systems don't allow you to advance timing. Any motor with coil packs instead of a distributor can't be advanced.
The reason E10 provides less power is because alcohol is harder to ignite than gasoline. That's why top fuel dragsters run on alcohol blends, since they run very high compression ratios.
Unless you make a change in the compression ratio of an outboard, use the manufacturer recommended octane fuel.