Fuel

[Ranchito]

I'll add one piece of info. to the discussion:

A few years ago, I remarked on an automotive forum that it puzzled me that consumer lawnmower engines definitely have a lot of problems with old 10% ethanol fuel, but cars did not.

A guy who frequented that forum and that worked on the technical side of the trucking industry solved the mystery. He said that the difference was that fuel systems of automobiles are required to be sealed, whereas the fuel systems of lawnmowers and most other small-engine devices were not sealed - i.e, were freely vented to atmosphere. Not only does that passively expose the fuel to air and moisture, but as ambient temperatures rose and fell routinely through night-time/day-time cycles, the gas tank "breathed" fresh air and moisture in and out as the air expanded and contracted with the daily temperature fluctuations - bringing a fresh batch of moisture into the tank every day to react with the ethanol in the fuel. Car fuel systems being sealed, they don't get a new batch of air and moisture constantly being pushed in and out of the tank.

That goes right along with what some of you said about moisture and ethanol interaction. But for me, it explained in particular why lawnmowers and other smaller engine devices don't tolerate aged ethanol fuel, whereas old ethanol fuel doesn't seem to bother running/starting quality of cars.

Not completely true. As one who works in the auto repair business, I have yet to see a vapor recovery system (EVAP) that seals the fuel system when the vehicle is not running. If this were true, the fuel tank, usually plastic, would expand like a balloon on a hot day and collapse on a cool night. The vent valve prevents this. The vent closes when running and a purge valve opens intermittently to vent vapors into the engine to be burned.

 

[xj61975]

I run E10 in my four stroke machines throughout the summer season, but for the final cut, I drain the e10 and switch over to ethanol free. It is important to get all the E10 out of the system before winter storage. My final act is to switch off the fuel shutoff valve, restart, and let the mower run out of fuel. This leaves a small amount of fuel in the carburetor bowl but no worries if it is ethanol free. I agree with Tbone0106 in that the stabilizers don't address the water issues with E10. Before ethanol free was readily available, I ran everything dry on a small amount of True Fuel or equivalent. Especially important for the two strokes. This method has worked well for me since the advent of "gasahol". Never a problem starting or running in the spring.

 

[saltair]

I use non-ethanol in all small engines. I also add seafoam to keep moisture out and keep engines clean.

 

[lkomnino]

Just add some water to a jerry can of it, shake and let settle. Ethanol shall mix with water and settle to bottom. Do it on bulk, or by the gallon.
Leo from across the pond ( Inger-land)

 

[mcspeed]

Interesting discussions here. I subscribe to the non-ethanol fuel in all my small engines. I have had 2-stroke line trimmer fuel intake hose dissolve in under 5 years using ethanol fuel. However I have a chain saw I bought new over 40 years ago that never saw ethanol free fuel for its first 39 years of life. No additives, never drain the fuel, may sit 2-3 years unused. I’m guessing the 2-stroke oil plays a role in preserving the fuel. Starts and runs well……go figure.

 

[kinard]

Is it really worth the extra price (Over a dollar a gallon extra) to get ethanol free fuel for mowers? I have a 18 hp Briggs & Stratton engine engine on my riding mower, I have a small small push mower and I have a 2-cycle weedeater. I’m in south Alabama, 65 miles from the coast. The past several years, I’ve cranked up the weedeater during the off growing season just to polish up what I may not have weed-eated earlier – just to run it for a little bit. I may or may not do that for the push mower. The riding mower is used to drag limbs to a burn pile so it gets cranked every so often in the ‘cold’ season. We’re not long out of growing season and we don’t have really cold winters.
I’m just wondering if there’s something I can do different or is there just no reason for the non-ethynol fuel at my location.
I appreciate your thoughts and time!

I use ethanol free gas in my two stroke engines (weed eaters, chain saws, hedge trimmers), but not in my four stroke engines (mowers) and makita blower. This is based on what my small engine repair guy recommended. I got tired of rebuilding carbs that gummed up using ethanol gas.

 

[eldowdy]

I've been using 10% ethanol fuel in my 27HP Briggs for 13 years. Nery a problem.

 

[schreib69]

As long as you're mindful to not store gasoline over 2 months there is no reason to use ethanol-free gasoline. Fresh or reasonably fresh gasoline won't damage a small engine. Check your manual and I think you'll see B&S agrees with me.

Good suggestion to the OP'ers question; for me, I will USE this guidance from now on with caveats:
-- after September when mixing 2 cycle gas, remember to put in stabilizer
-- after September only refill ONE of the gas cans(not both) to force me to use it up faster!
The whole problem centers around one's memory and mine SUCKS.
I have gone to buying paper tags with wires attached and noting at the end of each year when I drained the tank for winter and install stabilized gas. This is at least some help!

 

[schreib69]

I've been using 10% ethanol fuel in my 27HP Briggs for 13 years. Nery a problem.

Good to know.
We need more input like this.
Most folks have input that is opinions and info that confuses one variable with another-- They use BOTH Fuel stabilizer AND non-ethanol grade fuel.

Do you use stabilizer after things turn cold and you expect to have gas sitting around longer than a couple of months?

 

[Peva]

Not completely true. As one who works in the auto repair business, I have yet to see a vapor recovery system (EVAP) that seals the fuel system when the vehicle is not running. If this were true, the fuel tank, usually plastic, would expand like a balloon on a hot day and collapse on a cool night. The vent valve prevents this. The vent closes when running and a purge valve opens intermittently to vent vapors into the engine to be burned.

You didn't read everything posted - that was already addressed. I quoted the FSM for two of a certain car I owned in the past - I actually posted (attached) photos of those statements in the FSM. It explicitly stated that the valves open to ambient air close with engine/ignition off. In addition, some systems have a spring-loaded closed valve (similar to a check valve) that closes the system off below a certain pressure or vacuum but will overcome the spring pressure above a certain amount to prevent the problems you mention. So it prevents free flow of air like a normally-open valve or simple breather hole would. Depending on the design, that spring-loaded valve was in the purge valve or its plumbing, or built into the gas cap. The EPA requirements changed over the years to try to reduce or eliminate additional little bits of leakage, so system designs evolved in various ways to comply.