Tech2Tech: Ethanol, engines, empathy

By Dave Worden

As you probably know by now, the Environmental Protection Agency (EPA) recently approved E-15 (15-percent ethanol) for use in vehicles past 2007 model year. Before year end, all fuel nationwide will contain up to E-10 (10-percent ethanol), and E-15 will also be available at the pump. Confusion at the consumer level will increase the amount of damaged engines and fuel systems we have seen 10 fold! Dealers should educate themselves and their customers about using a proven solution to protect their investments. Many equipment and engine manufacturers are looking for, or approving of, fuel solutions that are specifically designed to combat the negative side effects of ethanol and protect all engines new and old.

Ethyl alcohol or grain alcohol is produced from corn, sugar cane, other cellulose crops (trees, switch grass, rice), which is causing widespread concern throughout the outdoor power equipment industry because it is very hydrophilic (water absorbing). The process for creating ethanol can be seen in the flow chart in Figure 1 (above).


Figure 2 — Carburetor with brown staining in the upper left-hand corner


Figure 3 — Carburetor with fuel passages that are blocked


Figure 4 — Notice the staining on the tip of the needle on the right


Figure 5 — Warning posterCarburetor and service issues are not new to dealerships. We are just in a cyclical period, or as I am fond of saying, “Reinventing opportunities to make money!” For those technicians that have been around for a while — which is the majority due to the average age of service techs in the OPE industry being 56 — we used to love the fully adjustable carburetors. Customers would play with the adjustments and eventually mess them up so badly that they wound up in the shop (usually on Saturday morning). We would reset them to the proper settings, make some quick coffee money, and send them on their merry way. Back then, there was something called seasonal blended fuel for summer and winter use, and if the fuel sat too long, it became stale and gummed up the carburetor. This was a nice service job for a technician, who would order a carburetor rebuild kit, disassemble the carburetor, clean it, and reassemble it. As a side note, how many of you technicians have a tray or drawer filled with Welch plugs that you did not remove? Come on. Be honest. I have seen thousands of them in technicians’ tool boxes!

The shelf life of fuel has changed, as have carburetors. Let’s talk about the stability of fuel and what we used to deal with before ethanol came onto the scene:

What happens when fuel is stored?

Fuel is made up of different organic compounds that can be affected over time by oxygen and other elements in the environment.
Stored fuel can oxidize and break down into gum and varnish deposits that clog fuel lines, carburetors and injectors. This can cause starting problems, reduce performance, increase maintenance costs, and shorten engine life.

Is draining fuel a good solution?

Draining fuel is a hassle that leads to other problems.
There can still be enough fuel left to form gum and varnish deposits unless fuel lines are blown.
Leaves bare metal exposed to air and moisture, which cause rust and corrosion.
Dries out gaskets and seals, which can cause leaks.
Drained fuel is a fire and safety hazard.

These issues were reduced with the use of fuel stabilizers and with seasonal blended fuels. If the fuel was left to sit and become stale, it caused parts of the carburetor to look like they do in Figures 2-4. Stale fuel gives the appearance of a brownish/tan color and can easily block the fuel passages necessary for the carburetor to operate efficiently. It also usually carries a strong odor and, if left long enough, it turns to varnish.

One option a dealership should consider is posting signs or posters in the shop, as well as the showroom and service write-up area (see Figure 5). This warning poster should help the service writers and hopefully increase fuel stabilizer sales. There is a line of thinking that if the owner buys fuel stabilizer, the shop loses service work. My take is well-informed customers will return for all of their service work and be less apt to argue over the bill if they have seen, heard, and been given the option to avoid a recurring service bill.

In case you cannot read the fine print in the warning poster pictured in Figure 5, a slightly edited version reads as follows:

“Why can’t I use gasoline left over from last year?”

Gasoline has a very short “shelf life.” It starts to lose its volatility after 30 days and starts to turn to varnish.

If you do not use the gas in a timely fashion, it will cause damage to your carburetor.

Emission standards do apply to Power Equipment, as well as your automobile!

The biggest difference is that you use your automobile much more often than your Power Equipment. With the Power Equipment regulations so strict, the carburetor is extremely vulnerable to dirt, debris and “stale” gas so…

Please use a fuel stabilizer and make sure your fuel container is clean and has the stabilizer in it.

Dirt, debris and ‘stale’ gas are not a manufacturing defect and cannot be covered by their Warranty Policy.

We will check your fuel system as part of our basic service and advise you of anything out of the ordinary.

Ethanol effects on carburetors and fuel systems

Materials which come in contact with ethanol (the higher the blend, the higher the risk of damage) must be capable under its hydrophilic and solvent properties.





Plain steel 

Stainless steel             














Neoprene rubber




Items that need to be considered by manufacturers:

1. Required product changes

a. Carburetor

b. Carburetor calibration

Main system
Idle system
Choke calibration
Accelerator pump

2. Carburetor material changes

3. Brass jets to bronze or stainless

4. Aluminum casting — Must evaluate for corrosion

5. Ignition system — Switch to higher energy with starting feature

6. Electronic Fuel Injection (EFI)

Fuel rail — Change to stainless steel
Fuel injectors — Change to larger mass flow rate
Regulator — Change for material compatibility (diaphragm OK, brass to stainless)
Electronic control unit (ECU) — New calibration
Spark plug — Requires wider-operating temperature range
Aluminum manifold/port — Evaluate for internal corrosion

The aforementioned notes and information will vary depending upon the amount of ethanol. The current “recommended” 10-percent blend has caused quite a few issues to date. Going to 15 percent or higher will exponentially raise the service issues. Now just imagine how and what E-85 is doing to the automotive industry!

As you can see, the effects of ethanol can be overwhelming! For OPE service technicians, it can lead to additional service work and a greater understanding of the fuels, fuel stabilizers and the procedures required to service the carburetors. This means you may be using all the Welch plugs in the rebuild kits!

 Dave Worden is the president of the Equipment and Engine Training Council (EETC) and a program director for SkillsUSA.

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