Ethanol burns hotter, bad for a small engines?
- Thread starter ruSSrt
- Start date
Fake news. See the chart below. Ethanol burns much cooler than gasoline, over 110*F cooler. The real reason to avoid ethanol in equipment that doesn’t see regular turnover of its fuel tank is that ethanol is very hygroscopic; this means it attracts water. Water does not burn and higher ethanol content fuels can become saturated with water and cause problems.
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They are saying that 10% is fine. The reason is wrong though. A fixed jet carb cant compensate for the higher ethanol content.
Some very old 2 cycles will burn through pistons on e10 if you “drive hard.
My Subaru 360 is one example as it is a lean burn automotive 2 cycle. On e10 you need to change the dizzy and timing, along with the spark plug gap and the enrichment AFR on the carb.
On a hot day if you don’t you can get quite a bit more power at the top end, turn more rpm’s before it self limits and potentially burn through a piston.
The reason this is is more to do with being able to overrev and generate more power than intended coupled with lean burn, no oxygen sensor and running near the edge to begin with.
For a governed piece of lawn equipment the above is very unlikely unless you regularly take your v twin lawn mower to 8000rpms
You burn through pistons because the fuel delivery (carb or injection) is not adding the correct amount of fuel and is therefore lean; stoichiometric on gas is 14.7:1, E85 is like 9.7:1, so you need a LOT more fuel to keep the combustion “happy”.
Newer small engine run lean anyways due to the fixed jet carburetors and EPA reg.
Yes and adding more lean is asking for trouble.
Properly jetted, small engines will make more power on alcohol fuels. This is because they cool the intake air significantly, leading to better breathing. Additionally, alcohol fuels can be higher octane, leading to the option to run more timing and more compression.
This sentence made my brain fibrillate.
This still won’t address the hygroscopic tendencies of ethanol-containing fuels.
FWIW any newer OPE that I’ve purchased says E10 is fine. The issue historically has been that ethanol is hydroscopic and will destroy fuel lines in older equipment. The newer stuff will run fine on E10. I usually try to find E0 to avoid the water issue.
Just my $0.02
Just my $0.02
This is the answer on a larger scale. Not sure E10 will cause the issue but from my racing days @SubieRubyRoo is correct you burn a lot more alcohol than gasoline when everything is the same.
Just my $0.02
As the nitrous guys used to tell me when I first started racing, “lean is mean (on parts), but fat is where it’s at”. Lean will usually make more power, all the way up to just before the point you’re helping the cleanup crew pick up chunks of your engine off the track surface. The problem is that line is so thin when you chase it you’re playing with razor blades.
A rich, but not overly so, mixture burns cooler because there’s essentially a small percentage of unburned fuel that is still cooling the combustion. When there’s not enough fuel, as in the case of running ethanol or methanol in something expecting pure gasoline, the lack of fuel means all that extra oxygen is essentially turned into an oxy torch… whose burn temp far exceeds what any aluminum piston can tolerate for even short lengths of time.
Hence, you either torch a hole through the piston, or if less lucky, get the top ring to expand enough that the ends touch, the ring begins to weld itself to the wall, and in some instances, basically pops the crown of the piston off like little kids do to dandelion heads. But with more carnage, and more crying.
Older equipment also probably doesn't have fuel systems that comply with the more recent evaporative emissions regulations, which could allow moisture into the fuel system (and I don't think moisture gets into these systems just from humid air, but from outside storage where it can get rained on...old Briggs engines had a fuel filler cap with a hole in the center of it, didn't seem like much was going to stop any water that landed on that cap from going right into the fuel tank).
I've been using E10 in my 2013 riding mower, I leave it in all winter, I store it in my garage, it always starts up in spring with no problem...and I've been doing this for 6 years now.
My Husqvarna trimmer purchased around 10 years ago has only seen E0 and stabilized gas. The darned carb still plugged up.
My old John Deere F510 had a non vented fuel system. Never drained the gas or had water issues in 24 years of E10 use.
My old craftsman pressure washer had a B&S motor with carb in tank, It had a vented cap. I had to throw the thing away as no way could you drain all the gas out of the tank and if you didn't then water built up in the bottom. About every other year had to take the carb and the tank off and wash it out.
Kind of.
The main way ethanol is bad for your engine is the ethanol absorbs a little bit if water and starts attacking everything in the small engines cheap little fuel system. Corroded zinc plated steel carb fuel bowl, the alcohol attacks brass carb parts and the rest of the carb made out of die cast. It can also cause some fuel lines to swell.
Does it "buen hotter"? Kind of maybe. The correct air fuel ratio to burn gasoline is 14.7 to 1. The correct air fuel ratio to completely burn E10 is around 12.5 to 1. So running E10 will lean them out, but every small engine I have encountered appears to be set to run E10.
I'll actually use E10 to tune a carburetor, I'll put E10 in an empty tank, then run it, install smaller and smaller carb jets till the engine sputters from fuel starvation at full load. Once I get some WOT sputter I'll turn it off and dump the left over E10 on some weeds that need killin and fill back up with ethanol free gas. Some times if the engine still runs a little funny, I'll put the next size up jet in.
Sometimes I wonder how I've gotten 31 years out of my Toro lawnmower, 24 years out of my lawn tractor and nearly as many years out of my string trimmer and chain saw when all we've had here in Southeastern Wisconsin is oxygenated fuel. All of this attacking of parts must occur elsewhere?