Question for you chain saw and weed eater guys.

Rat Rod Mac · Sep 5, 2017

Buddy flies airplanes so he brought me five gallons of 100 octane low lead gas with no ethanol. Guy at work says that it's to hot to run in my chain saw. Anyone know anything about this? I figured it would run just fine, but now I don't know and don't want to hurt my saw. Could mix with the recreational no ethanol gas that I'm running now I suppose. I mixed in some Sta-Bil so I'm hoping it will keep for the wood cutting coming up this winter.

RNeumann · Sep 5, 2017

Octane is the number given in reference to "resistance to burning". The racers need higher octane to prevent pre-detonation, pre ignition or pinging. The race engines have higher compression and regular fuel won't cut it.

It will be fine to use. If anything you could mix some regular unleaded in if you needed to lower the octane.

Btw- your friend's reference to it being too hot- the energy or hotness would be referenced by BTUs.

Larry Caldwell · Sep 5, 2017

That's very high octane, and will run just fine in your chainsaw, with the caveat that lead will cause cylinder head deposits, so you may have to take the engine apart and clean up the head once a year. You can't pour it into your car or pickup next year either, because the lead will poison the catalytic converter. The best choice for 2-cycle engines is the ethanol free unleaded premium you can buy at marinas or rural service stations.

RNeumann · Sep 5, 2017

More useless trivia- the lead was added to increase octane.

atsah · Sep 5, 2017

I wouldn't use it, your carb settings would need to be adjusted. I run non ethanol 91 octane ALL of the time in my small engines, I had to adjust the factory settings because they are set to 87 ethanol settings.

dodge man · Sep 5, 2017

It's good stuff, I'd probably blend it 50-50 with pump gas.

Maxify55 · Sep 5, 2017

I've never once EVER used anything but straight pump gas 87 oct with 10% ethanol and never once had a fuel related carb issue in ANY of my two cycle equip. or ZTR mowers.

That being said, I mow grass and brush year round. So none of my equipment ever sits for very long.

I am a stickler for fuel stabilization additives and clean carbs on all my stuff.

My neighbors and friends, on the other hand...:duh:

I spend an awful lot of time cleaning other people's carbs, though.

It's just tough saying NO, at times.

rekees4300 · Sep 5, 2017

Rat Rod Mac said:
Buddy flies airplanes so he brought me five gallons of 100 octane low lead gas with no ethanol. Guy at work says that it's to hot to run in my chain saw. Anyone know anything about this? I figured it would run just fine, but now I don't know and don't want to hurt my saw. Could mix with the recreational no ethanol gas that I'm running now I suppose. I mixed in some Sta-Bil so I'm hoping it will keep for the wood cutting coming up this winter.

Don't use it in your saw. I use Stihl MotoMix. It's expensive but has the proper octane and oil already mixed in, no Sta-Bil needed. All I have to do is pour it in the saw, no fuss, no mess, no hassle and the saw loves the stuff.

Premixed Ethanol-Free Fuel for Outdoor Power Equipment | STIHL USA

jaxs · Sep 5, 2017

At first I was going to agree with RNeumann but though itt better to say DON"T USE IT,bring it by my house so I can use it in mine.:biggrin:

RNeumann · Sep 5, 2017

jaxs said:
At first I was going to agree with RNeumann but though itt better to say DON"T USE IT,bring it by my house so I can use it in mine.:biggrin:

Exactly! It's got tot be 100 bucks in fuel!!!

prichard · Sep 5, 2017

RNeumann said:
Exactly! It's got tot be 100 bucks in fuel!!!

Not even close. 100LL generally is a little less than twice the price of regular unleaded. So 5 gallons should be $25 - $30.

Redneck in training · Sep 6, 2017

RNeumann said:
Octane is the number given in reference to "resistance to burning". The racers need higher octane to prevent pre-detonation, pre ignition or pinging. The race engines have higher compression and regular fuel won't cut it.

It will be fine to use. If anything you could mix some regular unleaded in if you needed to lower the octane.

Btw- your friend's reference to it being too hot- the energy or hotness would be referenced by BTUs.

Bingo.
100 octane gasoline has the same energy content as 87 gas. It has higher ignition temperature and burns little slower therefore it might burn exhaust valve in some 4 cycle engines unless the ignition timing is advanced few degrees. It shouldn't be a problem in 2cycle engines. If you worry about it mix it with 87.
It has tetraethyllead added to it so do not use it in anything with catalytic converter.

turnkey4099 · Sep 6, 2017

Maxify55 said:
I've never once EVER used anything but straight pump gas 87 oct with 10% ethanol and never once had a fuel related carb issue in ANY of my two cycle equip. or ZTR mowers.

That being said, I mow grass and brush year round. So none of my equipment ever sits for very long.

I am a stickler for fuel stabilization additives and clean carbs on all my stuff.

My neighbors and friends, on the other hand...:duh:

I spend an awful lot of time cleaning other people's carbs, though.

It's just tough saying NO, at times.

Same here. I've been behind a chainsaw for a minimum of 7 cord a year and now dowing over 20 every year. Never used anything but regular 10% ever and have never had a problem. I do run every saw dry and put them away for the winter, never leave fuel in a tank that I can drain. My snowblower and splitter get the same fuel, both have a shut off valve but no way to drain the tank. I shut off the fuel and run them till the carb is empty.

LD1 · Sep 6, 2017

100 octane is NOT hotter nor is it MORE powerful than 87.

Have no idea when or how all these myths about octane got started? Maybe just because the "race car" drivers are using it so it MUST be high powered right......not even close.

The guy that told you it was too hot....cross him off the list of credible when it comes to advise in similar topics as well.

Octane...in layman's terms, is simply how hard the gas is to ignite. Higher octane....harder to ignite. Period end of story. Octane has nothing to do with power level.

Compression in an engine makes heat. (This is how diesel engines ignite....compression ignition).

Well you don't want that in a gas motor. Pre-ignition or detonation are two common terms for it. Modern cars have knock sensors. If it detects this, it will pull timing (less power).

Since 87 octane is easier to ignite....if you have something designed for 87, there is no benefit at all to running higher octane. All you are doing is making it harder to get ignited. No, it doesn't burn cleaner, no it doesn't increase milage, or any other BS claim made.

As to the topic at hand....I'd run it in a saw no problem. Might have to do some slight tweaking to the carb tune, but unlikely. But it's no better than any other lower octane gas goy can buy that's Ethanol free

lennyzx11 · Sep 6, 2017

The higher octane allowed engines to be built with higher compression ratios because of the preignition or detonation point was raised in terms of how much pressure could be reached before detonation at a given timing setting.
More compression equaled more power. Hence race car engines running higher octane fuel.
Without advancing timing or upping the compression ratio to take advantage of the higher preignition point.... It's like driving a ferrari to the store to get milk. It'll do the job but kinda wasting the potential.

motownbrowne · Sep 6, 2017

It'll be fine in a saw. Might have to tweak the carb a hair. Maybe. Might have to tweak the carb a hair if it's raining, or winter, or whatever, but most people don't anyways, so you could probably forget all about it.

Personally i wouldn't run it, not because of how it'll affect the saw or trimmer, but because I don't want to be working in a cloud of lead fumes. Call me paranoid, or over cautious, and no, I don't have science to back this up, but that's just my feelings on the matter.

HillStreet · Sep 6, 2017

rekees4300 said:
Don't use it in your saw. I use Stihl MotoMix. It's expensive but has the proper octane and oil already mixed in, no Sta-Bil needed. All I have to do is pour it in the saw, no fuss, no mess, no hassle and the saw loves the stuff.

Premixed Ethanol-Free Fuel for Outdoor Power Equipment | STIHL USA

I just started using the Stihl premix in my 3 saws. I use them year round but they do sit idle for months. I was at the Stihl dealer and spoke with an old-timer that cut wood all his life. He said he uses the premix now and loves it, no more carburetor issues.

bigtiller · Sep 6, 2017

STIHL premixed fuel is convenient but at $32 per quart, no thanks. Even the cheapest brands are $5 a quart, still, no thanks.

Bravo Xray · Sep 6, 2017

Definitely use it. I buy avgas (100 octane, leaded, no ethanol, $5.50/gal) for ALL my non-automotive gas engines, 2 and 4 cycle, and it works great. Engines that were previously hard to start with regular gas (with ethanol) now usually come to life with just one pull. NO more worries about ethanol dissolving fuel lines/gaskets, etc. And the lead is a good upper cylinder and valve lubricant. Stabilize with Startron and it's good on the shelf for years.

Full disclosure, during mowing season I don't use it in my zero turn due to cost, but at the end of the season I'll run out all of the ethanol gas and fill the mower up with avgas and run it through the system.