Ethanol Anecdote

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If you own an older car, be advised. The high ethanol-content “gas” in use today can cause problems when fed to engines not made to use it. Not so much burn it – ethanol fuel has some advantages, including octane enhancement.

The problems arise when alcohol-laced fuel comes into contact with – and eats away at – rubber and plastic parts, including gaskets, rubber diaphragms, seals, o-rings and so on. The alcohol in the fuel also accelerates the rusting out of steel parts such as fuel lines and (in older cars) steel fuel tanks (most modern cars have composite plastic tanks).

Finally, ethanol-laced “gas” doesn’t keep as well – which isn’t a problem for regularly used cars but can most definitely become a problem for occasional-use older/antique cars (and motorcycles) that might not burn through a tank of fuel for several months.

I got an object lesson about all this the other day, when I spent some time over at my friend Graves’ shop. He has a ’63 Buick Special – which he stores on a lift in one of the not-used bays. We took it down to take it for a ride. The engine would fire, but stall out when you gave it any pedal. So, we popped the hood and looked. Peering into the carburetor while pulling the throttle arm revealed a weak-looking squirt of fuel into the venturis. Faulty/sticking accelerator pump, we reasoned.

A carburetor, unlike fuel injection, works off negative pressure. The vacuum created by a running engine draws the fuel from the carburetor into the intake manifold, and from there to the cylinders. But, there’s a catch. When you stab the gas, the vacuum signal momentarily decreases – which would ordinarily result in a stumble or stall – exactly the problem we were experiencing. The accelerator pump – assuming it is working – shoots gas into the engine to ward off the stumble that would otherwise occur due to temporary fuel starvation.

Our accelerator pump was clearly not working. But, why?

My buddy’s old Buick has the 215 aluminum V-8 and Rochester dual-jet (two barrel) carb, so it’s an easy job to access/repair the accelerator pump.

Well, it should be.

We pulled the carb off the engine and took it apart. It was filled with the debris of decomposing fuel – and rubber. The accelerator pump’s flexible rubber diaphragm was shriveled up and physically dissolving. The “goop” inside the carb was likely the admixture of the remains of the rubber, in solution with the ethanol-laced “gas.” I wish I had thought to bring my camera. But what was really startling is that my friend Graves had put a fresh accelerator pump in this carburetor just three years previously! The 10 percent ethanol in virtually all modern “gas” needed only that long to chew the thing to ruin. The carb’s internal passages were also partially occluded with crud and goop. Amazing the car even started. We cleaned the whole bugger out, put in a new (ethanol compatible) accelerator pump cup, gaskets and bolted everything back together. Car ran perfectly.

But for how long?

E10 (gas with 10 percent ethanol) is now the default standard “gas” almost everywhere. It’s very likely that E15 (gas with 15 percent ethanol) will be coming online within the next few years – probably replacing E10.

So, what should you do?

Keep in mind that even “modern” cars may have issues with E15. Some manufacturers specifically warn against using it. Only E85-compatible cars are for-sure ok. But that leaves a lot of cars that aren’t, because most new and recent-vintage cars are not E85 compatible. Anything older than about five model years likely isn’t.

Again – what to do?

For openers, let’s hope E15 is still a ways off.

In the meanwhile, see whether there’s a station in your area that sells 100 percent gas – not E10. Here’s a web site that lists such stations by region. If there is one in your area, fill up your old/occasional-use car with that – and hope it remains available for the foreseeable future.

Unfortunately, it probably won’t. Which is why it is probably time to update your older car’s fuel delivery systems with ethanol compatible components. That will typically mean replacing the following parts:

* Fuel pump and rubber fuel lines.

* Carburetor internals (accelerator pump, needle and seat, floats, gaskets – all these items will be in a rebuild kit).

You may also want to give thought to changing out the gas tank and any steel lines that are not stainless steel. If they’re original – or more than 20 years old – they’re probably already rusting from the insides out. The flakes of rust will get fed through the system, right into your engine.

Once that’s done you’ll want to take additional precautionary measures, including paying close attention to the vintage of the fuel in the tank. You now have a new incentive to drive your old car more often – so as to burn up the gas faster. Don’t let it sit for more than two months, if possible. Top off with fresh gas after every drive. And consider using fuel stabilizer (the major brand, Sta-Bil, now sells an ethanol-specific product; see here for info about that).

Hopefully – fingers crossed – that will be enough.

I suppose we’re going to find out.

Throw it in the Woods?



  1. A timely article Eric. I’m struggling with an 85 that has severe cold start problems and I’m beginning to think ethanol is the culprit, even though I have a composite fuel tank and stainless fuel lines. The symptoms are pointing to a vacuum leak in the intake manifold, which has quite a few gaskets and rubber lines I think may have been attacked by ethanol. I just finished pricing a complete intake refresh and it’s looking like about $1000 in parts and a couple of weeks under the car.

    I’m debating dumping the fuel in the tank before I start work since it’s almost 2 years old, but I’m pretty sure I have a vacuum leak. I’ll know much more tomorrow when my MityVac shows up.

    • We used to use propane, carb cleaner, or propane and squirt it around the carb and manifold to locate vacuum leaks. Or you can just disconnect lines one at a time and plug them up to see if you can isolate the leak.

      • I’ve used that method too, along with soap bubbles, but this is an EFI engine so it’s a bit more complicated. Without disassembling the intake you can’t see all the places it might be leaking.

        The procedure with this engine is to put about 2-3 bar of positive pressure on a vacuum test point then time the bleed down. After that, you start swapping out likely parts.

    • Scott,

      I’d dump that fuel. It’s almost certainly gone bad and is at least contributing to your problems. I’d also bet the ethanol has indeed done a number on your 85’s gaskets/seals. That car was built at a time when “oxygenates” were only being used part-time and not everywhere, either. If this car is a keeper, you might as well do it – because it’s gotta be done. I did the same with my TA (’76) and so far, so good.

      PS: If this is a carbureted unit, you might want to try richening up the mixture some. E10 is “leaner” than the pure gas that car was designed to burn.

  2. .BG Products, an automotive chemical specialty company, has two products that when used together, will disperse water into microscopic form and will protect metal and rubber parts. The part number for the kit that includes the water dispersing and system protection is 2028. I personally saw tests using several popular stabilized products and witnessed a BIG difference in their performance. .BG won hands down. This is not an advertisement for them, but an honest testimonial as a professional technician.

  3. Anyone know what year they switched over to the plastic tanks? I’m not sure what is meant by “modern” car, to me that’s anything less than ten years old. I’m looking for a used Toyota Corolla, and want to know which year to get for maximum longevity.

  4. Oh my Eric, is this a subject that hits home to me. I have a shop near Satans Toilet, er uh DC, that specializes in older, mostly english cars. As these are older cars, some with issues that caused them to be parked in the first place. Add the new crap gas and all hell breaks loose in the fuel system. I have seen it strip off coatings (rust proofing) applied to the inside of the tanks. I have a sample from a freshly re built set of carbs (filter, new hose and then the carbs)that failed quickly. Nothing passed thru the new filter (or so I believe), there was nothing in the new alcohol compatible hose, yet the freshly rebuilt set of carbs had what looked like partly dissolved brown sugar in the float bowls. I saved it, and dried it out, and it looks like corn meal. WTF is that?? I spend a lot of time fighting the effects of ethanol, and would join in that class action suit in a minute. My tool dealer related a story of a chap w/ a fairly new boat, who showed up to go fishing, and found his boat hull full of gas, as it has dissolved the fricking fuel tank. You can bet he is not the only one that happened to either. Can you imaging getting out your cherished Ducati round case desmo, and finding the irreplacable fuel tank melted away….I could go on. Damn them all.

  5. This year I started using the Marine Formula STA-BIL for the gas I store for the mowers and power equipment. It’s a bit pricey at just under $10 if I recall correctly, where as the regular STA-BIL is about $5 or so at Walmart. It’s possible there are better products out there, but this one seems to be the most widely available.

    So far it seems to provide good results. I tend to over-dose (since it says it won’t hurt), and perhaps that might provide some extra cleaning power.

    My main reason I started doing this is attempting to stockpile a few gallons of fuel for use with the generator when the power goes out. Last year around this time the power was knocked out for a week or more in some places during an unusual freak October snowstorm. It was cold, the heat pump (run by electricity) was unusable. It was a bad situation all around.

    The gas stations that had fuel and electricity had lines of cars down the whole street. It was pretty hectic. Even so, credit card processing was down in many places and they were only taking cash (good for me at least, since I try to use cash for everything). The general populace of clovers were hopeless though – unable to buy gas for their precious appliances as they’re so addicted to plastic payment methods.

    It definitely served as a wake up call to start taking some basic prepping steps seriously. Of course, there are still those that think you’re some sort of weirdo prepping for a doomsday scenario. I had a guy I went to high school with take cheap shots at me about “building a bunker” or something or other. Totally brainwashed Statist dependent on the rigged system to maintain his career as a lawyer. These people have no common sense – but they’ll be the first have to rely on others or the government to help them out of even the slightest situation. It’s because of people like them that we even have these ethanol problems in the first place.

    I’m curious if Ethanol is strictly an American thing or what? Are there any other countries that do this?

    • Hi D,

      A few months back I did an article about modifying a generator to multi-fuel use (gasoline and propane/natural gas). This really helps in re storage issues, since propane and CNG keep pretty much forever.

    • Brazil produces the most ethanol right after the US, but they seem to be doing it in a way that takes advantage of favorable sugar-cane growing conditions rather than producing it from corn. Wikipedia says their blend is 20-25% ethanol. I recall something I read a while back about fermentation being much more efficient for cane sugar over corn and the stuff basically grows like a weed down there any way.

  6. Hi Eric,
    Ethanol is a terrible thing to do to engines. It is hygroscopic (absorbs water from the air), has less BTU per gal. than gasoline ans for better and much worse is a great solvent. Unfortunately the corn lobby won’t budge on the issue and the politicans would rather have the vote instead of a viable solution. There is a better product out there and produceable from “organic stocks”.
    This product is Butanol.
    Higher BTU, non hygroscopic and can be burned with little modification to the engines.

  7. As I’ve noted before, ethanol did exactly that to my 1996 snowblower. It ate up the fuel line. When the mechanic dropped the float bowl, it was awash with tiny rubber bits. I’m lucky the ethanol didn’t destroy the carburetor.

    It also played hob with my old van, which no one could figure out why it wouldn’t run consistently. I dumped a couple hundred bucks into trying to find the cure, only to discover much later that a local gas station I frequented was selling ethanol gas without so labeling it (illegal in this state).

    To no one’s surprise, none of the fat-assed corn growers associations or subsidized ethanol producers around here offered to reimburse me for what their crap fuel had done. Such a deal: my taxes go into their pockets, they produce garbage fuel that damages my equipment, and I have to pay to get it fixed.

      • Eric,we have been using for years now the Startron,available at wally world ect. in boating section.A $9 bottle will they claim keep gas fresh and treat 128 gallons.As we all have older cars,two stroke dirt bikes and chainsaws ect. have been plagued with ethanol issues but this stuff seems to do the trick.I left a full tank of gas treated in my Husky dirt bike and she started and ran like a charm after 6 months,but then it is a Husky!This is just another example of corporate welfare and bad policy causing more environmental damage long term then the problems they claim at regulatory agencies they are trying to solve.Startron can be gotten in big bottles split among friends for more savings,probably true with Stabil and other products of a like nature.

  8. My Ace Hardware(small engines)has warned me about the ethanol and they recommend being sure I add stabilizer. While perhaps not an optimal solution, is this still a reasonable solution?

    • It’s worth doing – or at least, I think it is (and do so myself). Sta-Bil’s new product is designed specifically for ethanol “gas.” I’ve had good luck with their original product, so here’s to hoping…

      • Great tip, unfortunately a little late for me and my poor weedeater. Nonetheless, let me second this notion. I have a small (1 gal) gas can that I use for the 2 cycle mix used by my weedeater. I made the mistake of mixing up a full can of 2 cycle mix using E10 gas and attempting to use it over the course of a month. By the 3rd week, my weedeater could scarcely start at all. Taking off the air filter cover immediately revealed a gunked up air filter and carburetor and evidence of both rubber rot and significant moisture buildup. Removing the (recently replaced” spark plug revealed similar gunk in the cylinder. Granted some oil residue is not uncommon for 2 cycle engines, but this was excessive and manifested itself rapidly. A little searching found many similar accounts from other victims, and confirmation that pure “EZero” gas was the remedy for those whose small engines were still salvageable. My weedeater unfortunately never fully recovered. An electric model proved to be the best replacement option given the minimal amount of weedeating I do. Nonetheless it feels like a total sellout to a rod-and-piston man like me…

        • Likewise I got tired or rebuilding my previously reliable weedeater. Every. Year. So when Big Orange DIY box had a Ryobi cordless trimmer/blower bonus box, given I don’t do much weedeating, I jumped on it. Miss my gas, but don’t miss the drama.


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