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100LL in small gas engines

V

Vermont Supercub

Registered User
Stowe, Vermont
I'm tired of the short shelf life of regular auto gas in my chainsaws, weedwhacker, generator, snowblower, and other small engines. Seems like I'm always having fuel related problems. Whether it's the ethanol or just poor quality gas I don't know. I use Stabil in my gas cans and it seems to help a little.

Other than the additional cost are there any issues using 100LL in these engines? Fouled plugs? Can I mix it with 2 stroke oil for the saws?
 
I burned about 5 gallons of AvGas in my Harley-Davidson panhead once. Ran fine. Actually, it seemed to run quite a bit better. But I only did it that one time once when I was at the hanger on my bike and didn't have enough gas in it to make it to a gas station.
 
I've been running 100LL in lawnmowers, generators, Polaris Ranger, ATV's, Harleys, chainsaws, and boats that sit up all winter with no ill effects over many years. Only had a problem with one small chainsaw and resolved by adjusting for the high octane. Oil mixes fine with 100LL. Just my experience, I'm no expert on the topic.
 
It works fine, generally. I've run it in generators, MANY hours in outboards, etc, etc. Never had a problem, and it's good clean fuel.

These days, auto gas is who knows what.....

MTV
 
I usually run a 50/50 mixture, or a 75% mogas/25% avgas in the small engines with no problems. Left my chainsaw with 75/25 mix for 3 years without starting it, and it started on the third pull.
 
I run it in all the stuff you want to run it in. Works good, it's the only thing my Gator will run on. Mixes with 2 cycle fine. You won't see a cleaner carb.
 
My experience is all two strokes run fine, even better sometimes on 100LL than they do on auto fuel but my sawmill has a 4 stroke Briggs and Stratton V Twin and nothing fouls the plugs faster than a bit of avgas. Reverting back to unleaded auto gas cleans them again ...
 
Thats all I have run for 30 years. First 80/87 then 100LL.. Premix, or injection 2 strokes for snowmachines, outboards pre-mix, chainsaws, weedwhackers, no problems. Also have run my Honda 1000 generator probably 75 hours exclusively on 100LL, at about 70 hours it was misfiring, and I just had to clean some clinkers out of the sparkplug. 100LL is very stable and can be stored a long time unlike this crap they sell with oxygenatives in it. It is a great high octane fuel, that is stable and mixes well with 2 stroke oil. Only downside is it has some lead, so you need to look at the plugs and possibly carbon depoists on the piston/cylinders with real high use volumes.
 
Chevron Supreme works the best of all the brands of auto gas. No ethanol and it has additives to keep it from gumming up. The only thing I used in my jet skis and snow machine and never had to clean carbs at the beggining of the season.
 
My Yamaha 1000w gennies like 100LL alright. I had to change a plug after 11 years on one but aside from that they've been trouble free. My Honda 2000 inverter gennie not so much. I have to clean that plug every 15-20 hours if I run LL in it. As for 2-strokes? They run but according to radar guns and computer engine monitors a 2-stroke is happier with pump regular, at least up here where we haven't had any oxygenated fuel for many years. I suspect that makes our pump gas a little more stable than the stuff you lower-48ers get, too. My seasonal stuff like snowmachines, 4-wheelers, and boats use pump regular that's been stored for up to a few years in 55 gallon poly drums and it works just like fresh gas.

SB
 
Oh yeah. In my chainsaw, lawn mower, weedeater, and other small engines 100LL is the ticket. They sit full of avgas all winter and start on the second pull in the spring, while other guys are pulling the carburetors off to clean the stinky autogas gunk out..

Yep, the spark plugs only last 8-10 years, though..

The only use I've found for autogas is in my autos.
 
They sit full of avgas all winter and start on the second pull in the spring, while other guys are pulling the carburetors off to clean the stinky autogas gunk out..
Click to expand...
While my experience is a little different, I poured about a quart of Iowa E10/2cycle oil into the Lawnboy mower last May and it started on the first pull---was very surprised. The fuel had been mixed the previous August and that quart sat in a sealed/airtight 2 gallon plastic jug through the winter in an unheated garage. I don't remember running the mower out of fuel in Sept. when I cut the grass the last time for the season so there was probably a trace of fuel that sat in the tank for seven months. Not sure how you guys would rate that for "shelf life" but I don't think it is to bad.
 
the only thing that I have had NOT like 100ll was my honda weed eater.. 4 stroke, for some reason it just wouldn't run for beans.... everything else ATV Motor cycles mowers and even my Turbo Apex loves 100ll
 
Fortysix12 said:
When adding oil to gas, does that lower the octane?
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I'm not sure lowering the octane is the proper description but the oil will displace the available gasoline and will subsequently make the engine run leaner. Lots of guys in Alaska will add 2-stroke oil on really cold days thinking since the cold already leans a carbureted engine's mixture the oil will protect them. Many a guy has burned a piston as a result, too.

SB
 
Here is a picture of the jug I store the E10/2 cycle oil in. There is about a quart and a half left in there that was mixed in August and I'm pretty sure it will be good next April or May when I start the mower. Judging from the shape, I'd say there hasn't been a lot of air exchange since the Sept. air looks like it contracted quite a bit. That is the secret for keeping auto fuel in condition.
 

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Stewart, That is interesting that your yamaha 1000 likes 100LL. My Honda 1000 died after @ 200hrs. On a diet of straight or 50/50 mo-100LL....leaded up the valves and guides and trashed the top of the cylinder....I would not recommend running 100LL in any small Honda...2 strokes seem to love 100LL, except when you have to start them cold.....
 
Likes 100LL is an overstatement. It runs okay on it but honestly it runs better on car gas. Since my doctor found high lead levels in my blood I've quit burning LL in everything but the airplane.

SB
 
100ll


Hey there,
I've been running 100LL in all my equipment for the last 25 years, never had a single problem, from Jonsered chainsaw (same one for 30yrs.) 98 Skiidoo Summit 583, Troybuilt lawn mower, Craftsman snow blower. All 100% LL, no issues. Good luck, safe flying,
N8052C
 
I use it in my Quicksilver ultralight all the time it is a Rotax 447 and I mix it with Pennzoil Air Cooled 2 cycle oil and it runs great
 
@Nanook.... need to run some Marvel Mystery oil in the 100LL every once in a while in the little Hondas to clear the lead accumulations out. No big deal, and the things will run for ever. I have way over 200 hours, looks clean as a whistle in my 1000's combustion chamber due to the MMO servicing.
 
Fortysix12 said:
When adding oil to gas, does that lower the octane?
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Yes, oil reduces the octane.As an aside -FWIW- high octane fuels are not only more resistant to detonation but also burn slower than low octane fuels. Although avgas is GREAT for its long term integrity it is likely to cause plug fouling in lower compression engines that don't actually need it. They don't generate high enough peak combustion temps to vaporize the lead and it deposits in the plugs.Also, due to the slower burn rate,peak combustion pressure occurrs later than optimal in the power stroke and power is lost. In this case advancing the timing will help. Just put it back when returning to standard fuel. Personally I would think a 50% avgas blend would be a good compromise. And yes, our modern mogas is total crap!
 
And yes, our modern mogas is total crap!
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Perry, you sound pretty knowledgeable so I'm wondering if you know what the difference is between the 87octane E0 that is available now vs. 15 or 20 years ago here in Iowa. In other words, what hydro carbon molecules have been changed? I thought they were probably the same. I do understand that the gasoline portion of the fuel you guys out west get can't be used by itself.
 
Scooter, Thanks for the tip....MMO=coal oil, is that still true? There are going to be times that you just can't get around draining fuel out of the airplane for the generator....
 
MMO- light weight base stock cut with Stoddard's Solvent. A too-expensive additive to supplement already too-expensive gas so that it burns almost as well as the readily available and less expensive fuels recommended by the equipment manufacturers. Good idea! Do you get a hat with that? ;-)

SB
 
Iowa must have some super gasoline to mix with ethanol. Since it warmed up to about 32* today I thought I'd see if I could get the Stihl 017 chain saw to run. It's probably been 2 and 1/2 years since I ran it and it had just a trace of fuel in the tank. Found the jug that has fuel for this saw and it still had a little bit that was probably mixed 2 and 1/2 years ago(at least that long). I started pouring it in since it still looked green like when it was originally mixed up and started pulling the cord. I pulled quite a while before I figured I'd try putting it on warm run instead of full choke and it popped right off. It started and stopped numerous times before it ran good enough to go cut something. I do think I will drain and mix up some fresh E10/oil before I work it. Just feeling pretty lucky that Iowa must have better fuel since the rest of you guys would have had white goo in the tank and jug.
 
I've ran 100LL for years in Honda loading pumps for spraying and only problem I've had is replace a muffler because of corrosion. I have a 5.5 horse that I've used for at least 15 yrs and will still start on 3rd pull.
 
Fortysix12 said:
When adding oil to gas, does that lower the octane?
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Not initially, but mixed gas starts to break down after about 12 hours. General rule of thumb for those of use running Rotax power aircraft was to throw out mixed fuel more than a week old. That's part of why oil injection is so nice.

Chevron Supreme works the best of all the brands of auto gas. No ethanol and it has additives to keep it from gumming up. The only thing I used in my jet skis and snow machine and never had to clean carbs at the beggining of the season.​
Click to expand...

I always ran Chevron in my 150, never once tested positive for alcohol. And I never had any fuel system problems (unless you count noticably more carb ice issues). I run it in my Rotax now, and lawnmower. The lawnmower sits all winter and fires up first pull each spring.

Phil
 
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