Getting educated about gasoline...

[Big Wave D]

I've been reading a lot of threads on this board lately that deal with gas and seemingly how 'pathetic' our modern fuels are. They seem to be able to kill one's chainsaw or weed-eater by just being in the same vicinity.

So I appeal to the great mind trust on TBN for some education about the fuel we call "gas".

In my life, we went from Leaded to Unleaded, and I know the lead helped with engines running cooler. Then smog became a big issue and they started adding 'ingredients' to help with cleaner burning. Some were bad for groundwater polluting so we went Greener (Ethanol) for various reasons: helped the farmers, renewable, didn't pollute, etc...

Seems like A LOT of people LOATH ethanol being added to their fuel. What started around 5% or less is steadily growing to 15% or more. So I now read of people wanting to buy AvGas 100LL to use in their small engines, even at $4+ a gallon. They seem to think this a fare trade-off.

Now, I was always under the impression that gas would degrade to varnish over time, but some posts seem to indicate that that isn't necessarily true. So, if that is the case, what is in modern gas aside from Ethanol that makes it "crap" and what additives are breaking down and causing all of these carburetor problems with the gumming up off all the small orifices inside these small engines carbs.

Last thing. For this discussion, I'm not even going to touch the whole diesel debate on ULSD and Biodiesel. If you all can educate me about the Gas issue, I'd greatly appreciate your help in me bettering my understandings of fuel and how it can contribute to the health or destruction of my engines.

Thanks to all in advance

 

[Wis Bang]

Lead was an anti-knock compound that also protected the valve seats. Hardened valve seats cured that.

Replacing lead as an anti knock was MTBE [Methyl Terteriary Butyl Either] was an oxygenate that didn't form gummy deposits. It's problem was it is a Houdini class escape artist. It was difficult to keep in the transporting trailer and managed to escape from storage tanks and ended up in the drinking water.

Enter Ethyl Alcohol as an anti knock additive. No problem if it escaped to the environment. It is very hydroscopic, pulling moisture from the atmosphere and making the Ethanol, along with the myriad of hydrocarbons we call gasoline, form sludge and gelling up the tiny passages inside small engine carburation systems.

The breakdown means gasoline is not stable over 30 - 40 days. It's not so bad in your automobile since most of us use the fuel quick enough and injection systems operate at high pressure preventing the pluged passages your small engine carburator develops.

 

[Big Wave D]

Wis Bang,

Thanks for your post.

Is there anything about fuel from say 30+ years ago being any more stable? It seems like I've read some posts by older members that appear to be saying that gas from their youth was "pure" and "unmolested" (my words, but what I've inferred from their posts). Would 'straight' gas have a longer shelf life?

All of the AvGas 100LL threads seem to hearken to the fact that not only does it still contain some lead (though I don't see that being much help with modern small engines), but that it also is a "purer" fuel. Certainly no ethanol and probably no oxygenaters either. What type of additives a recipe airplane engine needs, I haven't a clue.

 

[DEWFPO]

Gasoline is complex. It contains approximately 350 hydrocarbon compounds. It is also modified from season to season and from area to area. Some have ethanol, some don't. I wouldn't call gasoline of 30 years ago 'purer' than the gasoline we have now. Just a different blend.

Federal and local regulations require certain additives to keep the fuel injectors clean so that they operate efficiently and thus produce less pollutants. Carburetors of 30 years ago didn't need those additives and hence the fuel back then didn't have them. As well catalytic convertors are very particular in what they ingest so fuels are blended to give them a long life, once again reducing pollutants.

Then you get into the whole political debate on ethanol. MtBE (Methyl-tertiary Butyl Ether) was also forced upon us by the EPA and used along side ethanol in gasolines. Gasoline rec'd one or the other but not both. After the feds finally realized what the industry was tell them all along (that MtBE should not be used in fuels), they relented and banned it.

I have personally kept 15% (gasohol) in my older 2-stroke chain saws, trimmers, mowers, etc... for well over 2 years and never have had a problem. Not one. Others have.... so there are many factors involved and just calling todays gasoline junk isn't accurate nor fair.

DEWFPO

 

[jonyyuma]

We have 10% ethanol added to most gas here. Pure gasoline can be still purchased at a few stations.Mileage climbs back up when using pure gas, and seems to burn better in my 4 cyl.. The Prez says, adding 15% ethanol to fuel will help the country. I say when it goes to 15 % , there will be other problems with autos especially older models. The old white gasoline, by American did not clabbor or gum up nearly as fast. They were taken over by BP here, cannot say if white BP gas still performs as well?Jy.

 

[Wis Bang]

The old white gasoline, by American did not clabbor or gum up nearly as fast. They were taken over by BP here, cannot say if white BP gas still performs as well?Jy.

I find that the Amoco/BP sold here is better than the other brands, I see at least 1MPG more and willingly drive 3 - 4 miles out of my way and pay about $0.05 more a gal for it.

Gasoline is considered fungible and frangible; the old Amoco distribution terminal in this area is still utilized by BP, it is separate from the others in our area though still pipeline supplied the still try to keep their product segregated.

From my gasoline hauling days, the 'brands' grouped around a terminal area will share product when necessary. Should the floating roof on brand X's regular tank get stuck and they develop a water problem, all of their stations will get brand Y's regular until the problem is fixed. Later brand Y will get replacement product from brand X somewhere...

 

[Skyco]

The old white gasoline, by American did not clabbor or gum up nearly as fast. They were taken over by BP here, cannot say if white BP gas still performs as well?Jy.

When BP took over they did away with all the premium Amoco "clear" gasoline around here...wish I could still get it. I have a now old dirt bike (98 Honda XR400) with the fuel tank made of white plastic. The "yellow" gas discolors it eventually, so I used to run all Amoco white gas in it for that reason and the fact it just ran well on it. Now I can't get it

 

[Big Wave D]

Thanks to all who have shared their knowledge on this topic. I've found it to be rather interesting and useful for future care and operation of my gas powered equipment.

Skyco:

I had a Honda VFR700 that I too thought ran best on the Amaco Clear fuel. It had a steel tank so Yellowing wasn't an issue. It just had a little more snap, pep, and better throttle response when burning the Clear.

Wis Bang:

I've never tracked my mileage with near the precision that you have so I found your post about the difference in how fuels from various suppliers caused the bottom line on your MPG to move up or down. It may not seem like much but keep adding that extra 1 MPG up over tankful after tankful and your wallet would start to see a bit of stretching of your dollars.

Jonyyuma:

We've had Ethanol in the gas where I live for years now. I am curious about your ability to buy straight gas though. How is it labeled so that you know it to be as such? All of our pumps have the little label saying that the gas you're buying can have X amount of Ethanol mixed in with it. Is it sold in a self-contained tank/pump like Kerosene?

DEWFPO:

Thank you for your in-depth description about what all is happening behind the scene before you even put the nozzle into your tank's fill spout.

 

[jonyyuma]

No ethanol is posted in large letters out front of the stations. The pump has the same sign. Ethanol here is 10% content ceiling. Yes, I worked at our local refinery for a spell. Plus living close to the river, I know the cheapie's get all of it from the same terminal and Barge..Unless you pay for it, you won't have addiitives. Plus, I do not BUY Chavez gasoline,,aka Citgo or express gas, just because.Jy.

 

[Big Wave D]

Jonyyuma,

Thanks for the info.

Nope. No stations in my part of the country display any such claims.

I don't know about the airport and their policy on selling 'to the public'. While I was employed there, I suppose I could have bought AvGas, considering I was one of the Line Techs pumping it everyday for everyone else.