100LL Avgas

Eric in IL · May 12, 2016

I'm thinking about switching to Avgas for the multitude of small engines on the farm that get used once a year.

Just wondered if anyone has experience with it.

Does it last a year without going stale ?

Is it ok for use in two cycle engines ?

Thanks to all responders.

Russ from MN · May 12, 2016

Is it really worth the extra expense? I don't have any problems with pump gas, E-10 in all 4-strokes and ethanol free 91 in anything I mix gas for. And some engines only get used once a year. One little generator (Coleman Powermate) had some problems and even though it's a 4-stroke I put 40-1 in it for storage, thinking it would prevent the oxidation that I was finding in the carburetor, and it seems to be working.

wilson ind · May 12, 2016

I use av gas in cat pony engines and other small engines. Seems to stor well. Yes its expemsive, however it seur works good for worn pony engines and the like. I HAVEN MISTAKENLY use it in my pulling CC Case. Wink.

Ronnie Budd · May 12, 2016

Avgas will store well for years. It is formulated for aircraft that often sit unused for a long time. It will work fine in two stroke engines also. It is expensive, but so is small engine repairs due to bad gas. You won't be using that much of it. Go for it.

old popper · May 12, 2016

Go for it! I use Avgas in the pony on my JD 720 diesel, and all my small engines....weed eater, leaf blower, chain saw, etc. It is the best thing since sliced bread.

dhermesc · May 12, 2016

Actually they advise that 100LL only be stored for 6 months to a year under proper conditions.

http://generalaviationnews.com/2011/05/15/how-long-can-fuel-be-safely-stored-2/

GVSII · May 12, 2016

(quoted from post at 07:52:44 05/12/16) Is it really worth the extra expense? I don't have any problems with pump gas, E-10 in all 4-strokes and ethanol free 91 in anything I mix gas for. And some engines only get used once a year. One little generator (Coleman Powermate) had some problems and even though it's a 4-stroke I put 40-1 in it for storage, thinking it would prevent the oxidation that I was finding in the carburetor, and it seems to be working.

At the end of their respective season and their'er going into layup they all get a good amount of 2 cycle oil in the gas.I run them until I can smell oil in the exhaust and see a little smoke then shut them off.When their season comes around they start easy and run good.

dhermesc · May 12, 2016

I tend to agree. I haven't had any carb issues with any of my small engines - and all are filed religiously with E10. A little Stabile and some Sea Foam (for good measure) and forget about it. The worst case is my Yamaha generator - it may sit for two years before I drain the fuel (and pour it into my tractor) and replace with fresh fuel.

Russ from MN · May 12, 2016

I have done something similar, especially on an old Wisconsin, I dribble oil in the primer hole when idling fast, next spring I starts right up!

JF in MI · May 12, 2016

Understand that 100LL (low lead) has something like 15 times the lead in it that auto fuel had back when they sold leaded gas. You could wind up with lead fouling issues. My aircraft stopped having valve issues when I switched to no lead auto fuel. Also, I'm not sure about today's oils and their 'ashless dispersent' (don't know if I spelled that right) content since there is no more lead in auto fuel meaning you might start getting sludge build up.

Mike M · May 12, 2016

I do pretty much just like you do.

CenTex Farmall · May 12, 2016

I know several people who are doing this without problems. It is true though that you will get lead deposit build up at some point. General Aviation aircraft get oil changed and spark plugs cleaned every 25 hrs. You'd be surprised how cruddy the spark plugs get in that time frame. However, they have less than state of the art carburation and usually run a little too rich.

Honestly, I haven't had any particular problems with regular pump fuel. I do try to keep the chainsaw fuel fresh and generator is kept with no fuel in it at all. I have one tractor I don't use much and it may sit 6 months before I start it. It fires right up and I haven't had any fuel system problems. It's under a shed though.

RWT · May 12, 2016

For the past several years I have been using name brand premium gas that dose NOT have alcohol. So far I have only stored over winter before it got freshened up. I pretty sure that is cheaper than avgas. And I do mean a major name brand premium. So far I can still find that.

I don't have any problem burning alcohol gas but it does not store well. And it will eat a hole in that plastic filter.

RT (my 2?)

fixerupper · May 12, 2016

I'll have to start using Avgas in the pony on my R. It's the only engine on the farm that gives trouble if old gas is left in it. The fuel mixer seems to let the gas turn to varnish for some reason. My '35 Deere A sits in the barn with the same old gas in it year after year but it always starts on the second tome over when I start it once a year. I do run the carb dry when I shut it down but the fuel shut off leaks just enough so the bowl is full the next year when I start it.

Russ from MN · May 12, 2016

Wow! I had no idea that any fuel had lead in it anymore, I am old enough to remember changing spark plugs every 10,000 mile because of lead, and I don't want to go back there. I don't change more than one spark plug a year now and that is probably in a old beater lawn mower. Besides a lot of that lead must of ended up in the air that we breath.

WGM · May 12, 2016

I have never had a problem with alcohol gas in any engine, large or small.

onefarmer · May 12, 2016

The local(St Johns,Mi) gas and oil dealer has 100% pure gas. I'd call around and see if one of your local suppliers does too. Then it'd be no lead and cheaper.

fixerupper · May 12, 2016

WGM it isn't the alcohol. Alcohol is a pure product, the gas they mix it with is junk. I haven't had any trouble with alcohol in my gas since the late 70's and into the 80's when it wrinkled a few accelerator pump diaphragms in the climate I am in here in Iowa.

MarkB_MI · May 12, 2016

It is a fact that avgas has a long shelf life, but you need to understand why. Avgas evaporates slowly because its Reid Vapor Pressure can be no more than 7 psi. The vapor pressure requirement is not intended to improve shelf life, but rather to prevent vapor lock at high altitude or on hot days. The lower the vapor pressure, the less volatile the fuel and the longer its shelf life.

There was a time when there was a big difference in the RVP of avgas versus auto fuel, but that's no longer really the case. Over the years, tightening emission standards have significantly lowered the maximum vapor pressure of fuel in many localities. In some places, it's the same as avgas: 7 psi. In other locations, summer-grade gas is allowed to be only slightly more volatile than avgas. Refer to the link below to see the maximum vapor allowed in your area.
EPA vapor pressure requirements

Rex Simpkins · May 12, 2016

100 Low Lead is great stuff, but do not use it in a engine like a Farmall Cub-- I used it in everything and it worked great in all except Cubs could not understand what was going on but they were sticking valves. Then I typed in problems like that with airplane engines and found a old bulletin for flat head aircraft engines sticking valves because so much lead was sticking to the valve stems. Switched the Farmall Cubs to non ethanol and the problem went away. Was that the problem? I do not know but it seems to be.

David G · May 12, 2016

I think it is a waste of money and will contribute to fouling plugs and valves.

Avgas will still leave the deposits that any other gas will,plus lead, it just evaporates a little slower.

1206SWMO · May 12, 2016

Me neither...I had lots more trouble 30-40 years ago than I do now..

buzzinduzzin · May 12, 2016

Back in the day we could get 80/87 avgas ( along with other assorted higher octanes). Then they phased out the assortment & told us to use 100 LL. 100LL has 4 times the amount of lead that 80/87 had, many problems developed on the lower compression engines. The E.A.A. applied for a S.T.C. ( supplemental type certificate) & after much testing were awarded same for a C-150. Then many others got on the bandwagon & several S.T.C.'s were granted. Our flying clubs C-172 & C-150 both flew many trouble free hours on 87 car gas. My chainsaw, weedeater, leafblower, etc all have had no problems with E 10.

NIK OWEN · May 12, 2016

U WILL GET OVER 50 HOURS ON 100LL BEFORE U HAVE 2 USE A PICK TO CLEAN THE LEAD FROM AROUND THE ELECTRODE...NO BIG PROBLEM...BE BLESSED, GRATEFUL, PREPARED...

GarryinNC · May 12, 2016

When Avgas evaporates, all that is left is a faint amount of blue dye, no 'varnish', no gummy anything. When left in small engines, no gummed up idle jets and main jets, etc. I have been using it in string trimmers, chain saws, small dirt bikes, 4 wheelers with no problems. They can sit all winter and start right up. Some complain of hard starting because of the vapor pressure, but I have not found that to be the case.
The string trimmer that I use the most will have some lead residue build up on the spark plug, mainly the ground electrode. If left alone it will eventually short across the gap, I clean it with wire wheel or even a pocket knife. The spark arrestor screens in the exhaust of trimmers and the like can also get the same build up, but like Nik Owen said, it takes several hours. Smells good when it comes out of the exhaust too, like the airport used to smell. I hate to see it phased out.

Garry

buickanddeere · May 13, 2016

(quoted from post at 12:58:09 05/12/16) Understand that 100LL (low lead) has something like 15 times the lead in it that auto fuel had back when they sold leaded gas. You could wind up with lead fouling issues. My aircraft stopped having valve issues when I switched to no lead auto fuel. Also, I'm not sure about today's oils and their 'ashless dispersent' (don't know if I spelled that right) content since there is no more lead in auto fuel meaning you might start getting sludge build up.

Wrong, that is an old wive's tale.
100LL has a maximum of 0.56g per Liter which is just enough to protect the exhaust valves of P&W and Franklin air cooled aviation engines .
Today if you can find a batch of 115/145 purple. Even it has been reduced to a max of 1.29g per Liter.
There was more lead in the bad old days of purple 115/145 from WWII until the 1980's.
As other posters have already noted . 100LL will readily turn to vapour in the carb/intake/combustion chamber for easy starting. However it's less prone to vapour locking in fuel lines.
100LL does not deteriate into gum, goo and varnish that attacks fuel system components.

GVSII · May 13, 2016

Always get a chuckle hearing people saying how terrible leaded gas is. Fouls plugs,bad for the environment, the list goes on. But it's still being used in recip. powered acft.

BarnyardEngineering · May 13, 2016

It's allowed in vintage aircraft because the miniscule amount of environmental damage done by a few thousand airplanes is minor in comparison to having those airplanes randomly dropping out of the sky on to fields, highways, playgrounds, homes, etc. with dead engines.

100LL Avgas

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