Here is one for you gearheads...

[Misty Blue]

We all know about the problems of using E-10 gasoline and storing it for an extended time. So I looked into aviation gasoline as an alternative.

I can buy the stuff at the Moultonborough airport for about five and a half bucks a gallon. Too much to put in the boats or cars but not too much for engines that don't get used often and sit a lot. An example is my home generator. It may sit with the fuel tank full for months, but when you need it, you need it.

So what do I know about AvGas? Well it is 100 octane. It has NO ethanol. And it is only distilled at the refinery, never "cracked" from other fules.

I have been told that I should not use it because it "burns hotter" than regular gas. I dont get it.

87 octane has 125,000 Btu/gal.

E-10 gasoline has 121,000Btu/gal.

Avgas has 120,200 Btu/gal.

So how does it burn hotter?

I am willing to pry open my pocket and spend the moola for fuel for my emergency equipment but I don't want to burn out valves, heads, etc. in the process.

SOWADAYA THINK?

Misty Blue

[Kamper]

That's the thing about octane. The higher the rating, the slower it burns. Also hotter and requires a higher temp to ignite.

It's the 3rd point that (IMO) is the most valuable part of high octane fuels. Although any spark plug will generate enough heat to ignite any gasoline, it is less lkely to pre-ignite (knock/ping) due to pre-ignition caused by hot carbon buildup.

The hotter burn helps to burn off that carbon too but not as much as people think. Higher octane fuels were promoted for use in vehicles with knock/ping issues. One company used the slogan "Drive your engine clean!" and added detergents only to thier higher octane levels. All modern name-brand fuel has detergents so it isn't such a big difference.

Since it burns slower high octane gas may not be fully combusted by the completion of the power stroke of an engine not designed for it, and you are dumping unburned fuel into your exhaust system. I think one of the functions of a catalytic converter is to crack unburned fuel into non-polluting components. If used in a system that does not have one, the gas may re-ignite when it leaves the exhaust. That's what makes the spectacular display at the drag races!

(And that's all I think I know about that!)

I guess it's a judgement call if you want to use this fuel to keep your genny on long-term standby status. Maybe you should take the precaution of a large clear zone where your exhaust pipe is, or a fire proof shield if it's in any kind of shelter. I prefer treated fuel and run mine periodically. The bulk of my emergency fuel is treated and in sealed containers.

Good luck!

[NHBUOY]

Kamper; The "spectacular display" at the drags is from Nitromethane and/or Alcohol fuel mixtures.

MistyBlue; I am NOT a fan of using AVGAS in non-performance motors, and I use CAM 2 and a mix of Super 91/93 to make sure I have enough octane to run the HI-PO stuff.

Stock motors don't require high octane, and, may not run correctly with too much.

In my chain saws, and other "small, STOCK, motors I DO run Super 91/93 with a stabilizer (I like SeaFoam).

There are MANY opinions on this. Good luck filtering through them. I know what has worked for me though.

[NoBozo]

AVGAS..otherwise known as 100LL.....The "LL" stands for Low Lead. If your equipment has a catalytic converter, this fuel will likely have an adverse effect on the converter.

100LL has a very fast evaporation rate....get it on your fingers and it evaporates fast enough that it feels somewhat like acetone evaporating. Some older gasoline engine aircraft that were designed for 100LL can sometimes be certified to burn "MoGas"..which was leaded automobile gas back before ethanol. I don't know if these older aircraft can be certified for E10 or not. :look: NB

FWIW: There was a guy I knew a few years ago who was very big into antique race boats. He had an old supercharged Offenhauser engine from an Indy Car from way back. He had a hydroplane built to take the Offy engine. The Offy was designed to burn alcohol. He intended to use gasoline in it. I don't remember if the gas was 100LL or not. The fuel burned too hot and the (aluminum) engine destroyed itself....melt down. $100K..Poof. :eek:

[Happy Gourmand]

Buy regular 87 octane gasoline...add a good stabilizer ( I still use Sta-Bil and have never had an issue) run your lawnmower, snowblower, chainsaw, generator...anything else designed to use good ol' 87 octane...and you will probably never have a problem either.

[Kamper]

@ NHBUOY

Sorry I confused you... The "show" is an example of hot unburnt fuel being reignited when presented with more oxygen. Doesn't matter if it's gasoline, diesel, or exotic fuel mixes. Fire-fighters know it as"Flash over" when hot fumes in an enclosed area explode when they open a door or window.

[gf2020]

Phantom Gourmand is spot on. Only use regular 87 octane unleaded fuel, add a quality stabilizer like StarBrite StarTron, and you will be all set.

http://mystarbrite.com/startron/

If you think the fuel in a 5-gallon jug is getting too old, pour it in to your car or truck and start over.

[NHBUOY]

As an "aside" on using higher than 87 octane. I use 91 or 93 not so much for the octane, but supposedly, the higher octane, over time, will stagnate and deplete itself at a slower rate, and be useful even if it drops a couple points over time.

That's my story, and I'm stickin' to it. :laugh:

[ITD]

I guess I don't understand what you are trying to accomplish here. I drain my generator after I'm done using it. It has a 5 gallon tank with a petcock. I close the petcock, run the carb dry (some have a drain in the bottom of the bowl), disconnect the fuel line from the petcock, attach a hose to the petcock and drain into a gas can. Use the gas in a lawn mower or whatever or pour it into a car. Reconnect the gas line and you are good to go, gas it up next time you need it and it should start right up. The draining process takes about 5 to 10 minutes, at one point, my generator started right up after being stored like this for 8 years. ( you need to store in a dry place)

As said before av gas has lead in it and cause problems like fouling plugs and so on, not to mention the exhaust is bad for you.

[NoBozo]

Just thought I would add this for those who don't keep up with Aviation Stuff.

Piston engine aircraft (The Cessnas, Pipers, the Beech Bonanzas, etc) use 100LL. (AvGas)

The next class (UP) of aircraft are Turbo Props. These are aircraft that have "Turbine" engines.....BUT: with a reduction gearbox, and a conventional propeller. They use Jet Fuel. (Kerosene).

The TOP class of aircraft are the JETS. Lear jets, Citations, Jet Streams, and ...Boeing 737s..and beyond. They use Jet Fuel..(Kerosene). :) NB

PS: I Totally LOVE this Technical stuff. :)

[Misty Blue]

From what I am getting from you folks AvGas is a bad idea for the small engines.

I do use 89 Fuel and stabilize it with either Stabil Marine or Star Bright for the boats. I guess that I will just put that in my generator and small engine tanks and leave them half full or dump them to the Exlporer every once in a while.

Any way, thanks and happy new year.

The bay froze on Wednesday. That is a sure sign of Spring!!!!

See ya soon!!!

Misty Blue

[gtxrider]

Try this stuff. SEF™94 Small Engine Fuel

http://seffuels.com/

[NBR]

Shoot an email to the motor maker and ask them. Memory says that 100 octane is just fine in outboards but memory has been wrong often.

[Biggus]

Big fan of 100LL here. I've got a vintage motorcycle collection, all small bore, under 400cc. Ethanol fuel loses octane over time where Av gas stays stabil. Perfect for engines that are used sparadically. Been running 100LL in all my small engines for several years now with no issues at all, including pre-mix 2-strokes. The greatest benefit is when I want to fire up an old bike that's been sitting for many months, they typically start right up without having to mess with the carbs.

Have not cleaned a carburetor since switching to 100LL

[D.C.Burrill]

We all know about the problems of using E-10 gasoline and storing it for an extended time. So I looked into aviation gasoline as an alternative.

I can buy the stuff at the Moultonborough airport for about five and a half bucks a gallon. Too much to put in the boats or cars but not too much for engines that don't get used often and sit a lot. An example is my home generator. It may sit with the fuel tank full for months, but when you need it, you need it.

So what do I know about AvGas? Well it is 100 octane. It has NO ethanol. And it is only distilled at the refinery, never "cracked" from other fules.

I have been told that I should not use it because it "burns hotter" than regular gas. I dont get it.

87 octane has 125,000 Btu/gal.

E-10 gasoline has 121,000Btu/gal.

Avgas has 120,200 Btu/gal.

So how does it burn hotter?

I am willing to pry open my pocket and spend the moola for fuel for my emergency equipment but I don't want to burn out valves, heads, etc. in the process.

SOWADAYA THINK?

Misty Blue

Use a qt. in 20-25 gallons it will dun good. To much will burn a hole in the piston! it will act as fuel system cleaner,to much can damage &it will run poor.

[Kamper]

http://en.wikipedia.org/wiki/Octane_rating

http://auto.howstuffworks.com/fuel-efficiency/fuel-consumption/question90.htm

http://chemistry.about.com/cs/howthingswork/a/aa070401a.htm

Time to read some real facts. You'll find: The amount of fuel in a given volume may have more energy value but combusts at a different temperature than the same volume of fuel with a different rating. It's not the octane level of a fuel that cleans your engine but the additives. Using a different fuel than your engine is designed for is actually less efficient in terms of power produced, fuel burned and money spent.

Enjoy!

[DBreskin]

That's the thing about octane. The higher the rating, the slower it burns. Also hotter and requires a higher temp to ignite.

Kamper points to some good information in the post #16, but post #2 is not completely accurate.

Higher octane indicates higher resistance to premature detonation from heat. When the piston compresses the fuel/air mixture in the cylinder it heats up. If compression is high enough the heat can rise to the point where the fuel ignites before the spark plug fires. If this happens, the fuel will begin to burn too soon and produce the characteristic knocking sound. The octane rating is intended to prevent premature combustion and has nothing to do with combustion initiated by the spark plug.

The octane rating does not affect how hot the fuel burns after it ignites. 87 octane fuel and 93 octane fuel will burn at the same temperature and speed after ignition, regardless of whether the ignition is initiated by premature detonation or the spark plug.