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More on Fuel And Fuel Additives - Fear the Corn?

Warning: Controversial Material!

I grew up in a farm family in the South, so I'm very fond of corn. Of course I like grits, but my favorite form of corn is high quality bourbon! I have personally benefited from crop subsidies and understand the benefit of the emerging ethanol (made from corn) fuel market to corn farmers. I am sympathetic to their issues.

However, I feel that ethanol makes a lousy fuel for internal combustion engines. In fact, lots of folks think corn is the least-promising bio-fuel of all. Unfortunately, this horse has left the barn - ethanol as a motor fuel is here to stay.

There is some slight advantage in reduced carbon monoxide with ethanol / gasoline blends. However, there are better strategies to achieve this worthy goal without making life miserable for vintage motorcycle owners. The issue is inherently controversial and complicated by various political, economic, social, environmental and agricultural policy issues. No matter - the ethanol lobby has done their job and we're now all forced the enjoy the consequences of a swift march to ethanol! Not only will you pay more for food products (due to competition for corn), your carbureted engines will not run as well as they should.

I'm not a chemist, but I am very concerned about the quality of fuel sold today. Most markets in the US now sell an E10 blend (10% ethanol) year round. Depending on local regulations, this information may or may not be revealed at the pump. Typically, this blend is marketed as "gasoline" which it is certainly not! In some markets, the ethanol concentration is even higher for "seasonal" summer blends. I don't think it is ethical for oil companies to sell "gasoline" that is diluted with any percentage of ethanol without full disclosure - no matter what local regulations allow!

None of this is good for vintage carbureted motorcycle engines...especially those will ultra small idle passages such as the GL1000, GL1100, GL1200, CBX and CX500.

Below is a summary of problems associated with fuels oxygenated with ethanol (like E10) documented in several Technical Papers by Chevron. I believe this is a credible information and I agree with these conclusions.

Update: 6/16/08: Curiously, I just noticed that Chevron has retracted those white papers from their website! But, similar info is published here by Fuel Testers.

1. Ethanol has less "energy" than gasoline so fuel mileage is slightly reduced. My own experience with ethanol blends has demonstrated this beyond a doubt.

2. Fuel Degradation: Oxygenated gasoline oxidizes and forms gums and deposits more rapidly than "pure" gasoline. These deposits wreak havoc on the internal passages in carburetors. The storage life of ethanol / gasoline blends is reduced.

3. Moisture Attraction: Ethanol attracts water. Lightly used, carbureted engines with small passages (like the GL1000) are prone to internal corrosion when stale, moisture-laden fuel sits in the bowls.

4. Fuel Tank Layering Effect: Gas-ethanol blends absorb water. The water may be condensed out of the ambient air or be residual contamination in the fuel tank. If enough water is absorbed, the fuel will tend to separate into two liquid phases: a top phase of nearly pure gasoline (and oil, in the case of 2-stroke fuel) and a bottom phase of water and alcohol. This water-laden mixture will make the engine difficult or impossible to start. To solve the problem, the separated mixture must be replaced with fresh gasoline....no fun at all.

5. Lean-out Effect: Oxygenated gasoline results in a leaner air-fuel mixture. This will corrupt the perfect air fuel mixture calibrations designed into your bike by Honda. The leaning effect will also tend to make the engine run hotter than normal. In extreme cases, engine damage can result.

6. Vapor Lock Problems: "Vapor lock" results from fuel vaporization which can make an engine stop during operation in extreme cases. It usually manifests itself as very hard starting when the engine is fully warm on a very hot day. Vapor lock prevents normal output from the fuel pump since it's designed to pump liquid not vapor. Gasoline blended with ethanol increases the likelihood of vapor lock.

7. Materials Incompatibility: Older engines such as vintage motorcycles have experienced many problems with rubber parts (fuel pump diaphragms, needle valve tips and seats, fuel lines, gaskets, etc.) when first exposed to oxygenated gasoline. Replacement fuel system parts (such as all of the products available from Randakk's Cycle Shakk) have been engineered to be compatible with oxygenated gasoline.

8. Solvent Effect: Oxygenated gasoline may loosen deposits from fuel system surfaces (especially fuel tanks) because it is a better solvent than conventional gasoline. The suspended solids can plug the fuel filter and carburetor passages. This is most likely to occur when older equipment is first fueled with an oxygenated gasoline. On the plus side, a pristine clean fuel system will stay cleaner using fuel blended with ethanol.

What about E85?

Higher concentrations of ethanol are known to cause disintegration of rubber components. E85 (85% ethanol) must absolutely be avoided and not used under any circumstances...even emergencies. It will ruin the rubber fuel system components in any vehicle that is not certified as a Flex Fuel vehicle.

So what can you do?

Even if you disagree with my views on ethanol, here's some solid advice on managing the fuel in your bike's tank.

Stabil Marine Formula - this is the only fuel stabilizer I use and recommend!

Use a fuel stabilizer (like Sta-Bil) year round in every tank! Stuff happens and you never know when the last ride of the season will be. There is a newer version - Stabil Marine Formula that has merit. The marine formula version has extra cleaning and corrosion prevention agents...both useful to fight the negative effects of ethanol.
Use Marvel Mystery Oil in every tank of fuel to prevent fuel system corrosion. Follow the directions on the bottle for correct "recipe" which is 2 oz of MMO per 5 gallons of fuel. The will keep the internal, moving parts of you carbs lightly lubed. MMO is also very effective at retarding rust inside the fuel tank. Note: MMO is not necessary if you use Stabil Marine Formula. That product already has sufficient lubrication agents.
Run your motorcycle to a full heat cycle (until the radiator fan comes on) each time you ride it. Having fresh fuel flow regularly through fully warm passages is the best defense to keep them clear.
Ride your motorcycle frequently and for long distances whenever possible. Lightly used bikes have more problems with oxygenated fuel.
Get a heated vest, winter gloves and perhaps a windshield to extend your riding season. The less your bike sits the better!
Keep your tank fuel full when the bike is parked (reduces water absorption)
Use regular grade fuel...not premium. Regular is somewhat less volatile than premium and resists going stale a bit longer. Besides, unless you have a modified engine you're wasting your money on premium. If your bike knocks and pings on regular and seems to run better on premium, then you probably have a carbon buildup on the top end that needs attention. Avoid octane booster products as well.
Pros and cons on this one, but here's my advice: don't drain the fuel bowls during a typical winter lay-up of 3-6 months. I believe you are better protected from problems by having the carb bowls full of stabilized fuel for short lay-ups like this. Longer lay-ups are a different matter however.
Buy the best brand of gasoline you can find. Never buy gas when the fuel tanker is unloading. I recommend a so-called Top Tier gasoline. These brands of gasoline have superior additives packages, better consistency and stricter handling standards. They are recognized and recommended by major auto companies to ensure optimal engine performance and reduce emissions.
"Rotate" you fuel. When the fuel in any of my lightly-used bikes reaches 6 months of age, I transfer it to the large tank in my truck for digestion. Then, I put fresh fuel back into the bike.
DON'T BE TEMPTED TO USE E85 (85% ETHANOL) FUEL UNDER ANY CIRCUMSTANCE. E85 stations are popping up in my area. For fear of a tanker truck fueling mistake, I avoid them completely.

Note Regarding Randakk Cycle Shakk Products:

All internal carburetor parts offered for sale by Randakk's Cycle Shakk are approved for use with gasoline. The materials are long-established to be impervious to gasoline by the chemical firms which provide the materials. They will also tolerate a reasonable amount of ethanol in the "gasohol" fuel which is commonly marketed as gasoline in most markets in the US (with or without notice at the pump). E10 (10% ethanol) is an acceptable fuel as well as "seasonal" fuel (15% ethanol) which is marketed for summer use in some markets. This is the maximum recommended amount of ethanol in fuel marketed as "gasoline" for use in carbureted engines. Avoid ethanol altogether if you can for the reasons cited above.

What About Fuel Cleaner Additive Products?

Carb cleaning products intended for use in the vehicle's fuel tank are not a panacea. In fact, continuous use of in-tank fuel cleaners or using in higher concentrations than recommended is bad and can lead to premature destruction of internal carb rubber parts. GL1000 Float bowl gaskets in particular are prone to shrinkage in the face of fuel additive abuse.

The fuel system cleaner I recommend is the Yamaha Carb Cleaner product for "on bike" dirty carb rehab efforts...it's effective and harder to misuse. Put the Yamaha product in the fuel bowls only...not in the fuel tank! More here.

What about Sea Foam? Is it safe?

Maybe.

I regard the use of this product as mostly wishful thinking. Used as such, it is likely safe for internal carb parts. Indirectly, however, it can cause some problems as I explain below.

First, here's some information I received recently from Matthew Hanson of the Sea Foam Company after this Tech Tip was originally published:

My name is Matt Hanson and I work for the Sea Foam Company. I have just finished reading through the "More on Fuel and Fuel Additives" section on your website and I was impressed by your understanding of the problems we face with fuel and fuel additives today. Even your comments about over treating a fuel system with cleaning chemicals is right on the money because nearly all of them (other than Sea Foam) contain some kind of caustic chemical from methanol to MEK and xylenes and many other rubber and plastic eating compounds.

Sea Foam is actually one of the only additives on the market that does not have this problem. 100% of the contents of a Sea Foam can are pure petroleum. They are extremely high quality oils that are far less corrosive than gasoline and have absolutely no effect on rubbers, plastics, silicones or any other delicate material. You can test this by pouring some Sea Foam into a styrofoam cup. It will not damage the Styrofoam no matter how long it sits in the cup. You can go a step further and place some rubber parts into the cup to soak in the Sea Foam - the more delicate the better. Sea Foam will cause no damage and will not even swell the material.

Sea Foam was originally developed for use in outboard motors in the 1930's and was safe for every cork gasket and rubber diaphragm that chemical additives would have destroyed. The formula has not changed since the 1930's and Sea Foam remains the safest additive on the market.

Sea Foam is the only product on the market that is 100% safe to use in every tank at any concentration and it will actually address many of the fuel related problems you identify. For more information on Sea Foam products see our web site at: www.seafoamsales.com or feel free to contact our technical service department at (952) 938-4811 Thank you very much."

-Matthew Hanson

My view on Sea Foam - there are better fuel system cleaners, better fuel stabilizing products and better fuel lubricity products available.

I'm still reluctant to recommend putting most fuel cleaning agents into old fuel tanks. That can loosen crud and add to your misery. I don't ever use Sea Foam myself for that reason. If you have any fuel tank issues, the use of Sea Foam should be avoided in my view.

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