Let me start with a
little bit of background. Growing up, I detested gasoline powered technology. Except for the cars my parents drove, nothing gasoline powered ever
started properly, let alone on the first try. When it came to my toys, my gas
powered free-flight helicopter and control line planes took forever to get them
to start properly. Then when I was old enough to mow the lawn, I dreaded having
to start the mower. It would take dozens of pulls to get that sucker started,
especially at the beginning of the summer when the mower hadn’t been used in
months.
This frustration
continued until I bought my first home in 2012. The prior owners provided a mower that came with the house,
but I needed something most substantial, so I bought a walk behind trimmer
mower. It worked fine the first season, but then when I tried to used it the
second season, it wouldn’t start. I know it had oil and gas (I remember that it
had at least half a tank of gas when I stored it the prior fall), so I couldn’t
figure out what the problem was. If you know anything about gasoline powered
lawn equipment, you already know what I did wrong here.
Eventually I emptied the
gas tank, poured in fresh gasoline and tried it again. After a few dozen pulls
on the starter and several pushes on the primer bulb (or maybe it was a purge
bulb, I don’t remember), it started just fine. I learned a valuable lesson that
day and the more power equipment I’ve purchased, the more I’ve learned about
how to properly care for and store them when not in use.
Now, all of my outdoor
equipment, from my Stihl BR600 Magnum backpack blower to my cheapo Bolens BL110
string trimmer all start perfectly, within just a few pulls on the starter. They
sometimes start on full choke. But one thing I still haven’t figured out or
fully understood is gasoline storage.
I’ve done a lot of
research online about the drawbacks of ethanol gasoline, as well as how
gasoline is a difficult fuel to store for anything more than a few months. But
most of what I’ve found is anecdotal or without any reference to experimental
data. So I wanted something more tangible and concrete as to why storage
additives work and what ethanol gasoline is the scourge of lawn equipment
everywhere.
Therefore, I decided to
conduct an experiment. I would compare how E10 gasoline compared to ethanol
free gasoline with respect to long-term storage, as well as examine a few of
the more popular gasoline storage additives on the market today.
I decided on
using Sta-bil Storage and PRI-G. If I had the time and money, I would have
tried a few more additives, such as Sta-bil Marine. But the more I tested, the
more fuel and equipment I’d need. Basically, each new additive I tested would
result in roughly an extra $25 in the cost of this experiment and supplies. It
also required the storage of more gasoline in the garage, so I had to draw the
line somewhere.
This is the first blog
post in a two part series where I explain my methodology and document the
beginning of this experiment. In two or three years, I will finally test my
samples and upload my results for you all to see.
Methodology:
Samples
I wanted to test both
E10 gasoline versus ethanol free gasoline, as well as the Sta-bil Storage and
PRI-G additives. Therefore, I originally decided on using the following 6
samples:
- Ethanol free gasoline
with no additives
- E10 gasoline with no
additives
- Ethanol free gasoline
with PRI-G
- E10 gasoline with
PRI-G
- Ethanol free gasoline
with Sta-bil Storage
- E10 gasoline with
Sta-bil Storage
After doing some
research about PRI-G, I read that it could keep gasoline “fresh” for many, many
years (even indefinitely) if you added more PRI-G every 6-12 months. So I
decided to add the following sample:
- Ethanol free gasoline
with PRI-G, then more PRI-G every 9 or so months.
I’ve also heard the
benefits and enjoyed the convenience of TruFuel, so I decided to put their 2
year and 5 year storage claims to the test. Therefore, I added 2 more samples:
- 1 can of TruFuel 50:1
unopened (advertised as lasting 5 years in storage)
- 1 can of TruFeul 50:1
opened (advertised as lasting 2 years in storage after opening).
This gave me a total of
9 samples to store for several years and test the results.
Methodology:
Storage Containers
Now that I knew I wanted
to test 9 samples, I needed 9 containers. Because TruFuel comes in a can, I
didn’t need separate containers for them. That left 7 more containers to find. I debated for a
while on what to use.
I was originally going
to use liquid fuel stove fuel bottles, but decided not to because most of them
wouldn’t handle E10 gasoline very well (they’re typically made out of an
aluminum alloy) and the ones that could handle E10 were more expensive than 1+
gallon fuel cans. But the biggest reason why I decided against fuel bottles was
because it wasn’t a realistic method of storage.
No homeowner or
landscaper is going to store his or her lawn equipment fuel in a 800 mL, 1
liter or 1.5 liter camping stove fuel bottle. And from personal experience, I
know modern gas cans are very airtight, so much so that they bloat as the
gasoline breaks down and partially turns to vapor or gas (thanks EPA!).
Therefore, I decided on using a conventional gas can that you could find any
hardware or big box store. I choose the smallest size available, which is the
1.25 or so gallon size. I went with the Ameri-Can from Scepter due to their low
cost (under $9 from Walmart).
Caption: Brand new
Scepter (Ameri-Can) 1+ gallon gas cans
Attribution: Author’s
Own Work
I know that oxygen and
gasoline don’t mix well when it comes to storage, so I knew that I would fill
each gas can mostly full. As a result, I decided on putting 4 liters in each
gas can (I used liters because 4 liters was a tad more than 1 gallon so there’s
less air space in the gas can. It would also provide enough fuel for testing later
on and would make figuring out ratios with the Sta-bil and PRI-G easier).
Summary
of Samples for Testing
- Unopened 50:1 TruFuel
- Unused, but opened
50:1 TruFuel
- 10% Ethanol gasoline
- Ethanol free gasoline
- 10% ethanol + PRI-G
- Ethanol free + PRI-G
- 10% Ethanol + Sta-bil
- Ethanol free + Sta-bil
- Ethanol free + PRI-G
with 15 mL additions of PRI-G every 9-12 months or so
Samples
for Testing: TruFuel
Caption: The 2 cans of
50:1 TruFuel for testing
Attribution: Author’s
Own Work
Samples
for Testing: Gasoline
Caption: Ethanol Free Gasoline
Attribution: Author’s
Own Work
Caption: E10 gasoline
Attribution: Author’s
Own Work
I also took the time to
confirm that the E10 gasoline had ethanol and that the ethanol free gasoline
had no ethanol. I did this by taking 200 mL of gasoline and adding 20 mL of purified
water.
Caption: E10 gasoline
with water
Attribution: Author’s
Own Work
Caption: Ethanol free
gasoline with water
Attribution: Author’s
Own Work
Notice something
interesting? After adding 20 mL of water to the ethanol free gasoline, I got 20
mL of water out. The graduated cylinder shows about 18.5 mL due to a little
spillage on my part.
But when you look at the
graduated cylinder containing the E10 plus water “mixture,” I was only able to
remove about 25 mL of water and ethanol mixture. Assuming the 200 mL of E10
gasoline had 10% ethanol, that meant there should be 20 mL of ethanol in the
E10. Combined with 20 mL of water, and I should get at least 35 mL of clear
liquid separating from the gasoline (I know that if you add equal parts of
water to ethanol, you get slightly less volume than double the volume of either
ethanol or water – thanks Bill Nye!). But notice that I only got 25 mL. This
means that the E10 gasoline was only 2.5% - 3.5% ethanol based on my estimate.
This isn’t to say the
gas station mislabeled their gas. After all, their signs always say “this
gasoline may contain up to 10%
ethanol.” And I’m not surprised the gasoline doesn’t have 10% ethanol, but I am
surprised it only has as little as 2.5% by volume. And no, I didn’t have
contamination from ethanol free gasoline still in the pump and hose because I
purchased this E10 gasoline from a station that only carried E10 gasoline.
If my calculations or
understanding are incorrect, feel free to correct me in the comments below. Regardless,
my ethanol free gasoline was truly ethanol free and the “E10” did have a
measurable amount of ethanol in it. In case you’re wondering, I purchased both
types of gasoline during the afternoon of May 30, 2018 and created and stored
the samples on the evening of May 31, 2018. Both types of gasoline were rated
91 octane using (R+M)/2 method.
Samples
for Testing: Additives
Caption: PRI-G for small
engines
Attribution: Author’s
Own Work
Caption: The back of the
PRI-G showing its package date of January 6, 2017
Attribution: Author’s
Own Work
Caption: Sta-bil Storage
Attribution: Author’s
Own Work
Caption: The back label
of Sta-bil Storage showing codes I can’t decipher.
Attribution: Author’s
Own Work
I purchased the Sta-bil
from Lowe’s on Monday, May 28, 2018 and ordered the PRI-G from Amazon.com
around the same time. Per http://priproducts.com’s FAQ page, PRI-G is supposed
to last indefinitely in an unopened container. Then once opened, it will last 3
years.
I chose the small engine
formulation of PRI-G because it would be a lot easier to measure out the proper
ratio for gasoline. Regular PRI-G has a 2000:1 ratio, so my 4 liter gasoline
sample would only need 2 mL of PRI-G. On the other hand, PRI-G for small
engines requires a 320:1 ratio, so I would only need to mix 12.5 mL (I actually
measured out 15 mL, and I’ll explain why in a minute) of PRI-G additive into 4
liters of gasoline. It’s a lot easier to measure 12.5 mL than 2 mL.
Procedure
Step 1: I labeled each
gas can in three locations using a sharpie, pencil and ballpoint pen. It’s
overkill, but the last thing I want is to lose track of what fuel is in what
container in case I spill gasoline on the outside of a fuel can or the pink fades over time.
Step 2: For my controls,
I poured in 4 liters of gasoline into the gas can then closed the cap tightly. No additives were mixed in to either sample.
Step 3: For the samples
that had additive added, I poured in 800 mL of fuel, added 15 mL of Sta-bil or
PRI-G, then added another 3.2 L of fuel. I then closed the cap tightly, shook
the can 10 times, then set it aside. I did this for all 5 samples that had an
additive added.
I used 15 mL instead of
12.5 mL because it’s easier to measure, adding extra additive doesn’t
hurt anything (per Sta-bil and PRI-G’s website) and I knew a little bit of the
additive would be left on the inside of the graduated cylinder, so not all of
what I measured in the graduated cylinder would make it in the gas can.
I started with 800 mL,
then added the additive, then added the 3.2 L of fuel to assist in the mixing
of the additive into the fuel. Besides shaking the gas can 10 times, I wanted
added agitation of the fuel and Sta-bil or PRI-G.
Step 4: Placed all 9
samples into the back corner of my garage. This is a fully enclosed portion of
the garage, although it’s not air tight. Any changes in temperature and
humidity are quickly felt inside the below pictured storage location.
Caption: Storage
location of the 9 samples in my garage.
Attribution: Author’s
Own Work
Caption: Samples that
have been prepared.
Attribution: Author’s
Own Work
Future
Plans
The samples were created
on the evening of May 31, 2018. After at least 1 year, but preferably 2 or 3
years, I will test each sample in a two stroke engine. I don’t know exactly
what I will use right now, but I may use my Stihl MS 170. I plan to flush the
engine with clean, fresh fuel, then pour in the fuel sample to be tested. I
will take both subjective and objective measurements. For example, I will
observe how easy they are to start and how many pulls it takes. Then I will
measure idle RPMs and wide open throttle RPMs with a tachometer. Exactly how I
will measure performance is subject to change. I plan on asking for advice on
message boards in the months before I actually perform my tests.
I will also have a
record of the temperatures and dew points for the entirety of this test. I plan
to get my weather data from www.wunderground.com.
