high octane fuel concern

[fatboy999]

Just wondering if high octane fuel (91 and 94 octane) will damage the 2 and 4 cycle motors. We live in a cold climate and was suggested to run high octane fuel in the winter so the motors will start easier.

 

[fried1765]

Just wondering if high octane fuel (91 and 94 octane) will damage the 2 and 4 cycle motors. We live in a cold climate and was suggested to run high octane fuel in the winter so the motors will start easier.

I can't imagine that it would.
I use 100LL (low lead) aviation gas in my 2 & 4 cycle small engines.
Ethanol free gas is not available in my area.

 

[LD1]

Alot of people are totally idiots when it comes to octane and just what it means.

High octane, all else being equal, will make your saw start HARDER in the winter.

Think about just what octane is.

Octane is the gasoline's resistance to detonation.
that means higher octane....means harder to detonate.....and burns slower.
Remember, it used to be they put lead in gasoline to make it higher octane. You think that lead magically made the gasoline soooo much more powerful like many people magically think? NOT.

High comressions need high octane so the gas doesnt ignite TOO EARLY.
On modern cars that require high octane, the computer can compensate by pulling timing (less power) if you run too low octane. Thus there "seems" to be a big performance increase going to a higher octane. But in reality, you are just running the correct octane to get full timing advance.

Run the octane rating that is called for. Anything above that (again all things being equal), is a total waste of money regardless of what BS anyone tries to sell you on.

I hate the "regular" "MID" and "premium" nomenclature on the pumps. Got too many people brainwashed into thinking "premium" somehow means better. Would people still have this opinion if instead of calling it "premium" they called it "we loaded this fuel with a bunch of stuff to make it burn slower"

Now when I say "all things being equal" earlier......ethanol is a game changer.
Around me.....all grades have the same ethanol content. Unless you specifically seek out a station that sells E-free and charges $1.50 MORE per gallon for it. But I'd imagine there are still some places where 87 octane has the 10% or whatever ethanol, mid is a little less, and premium little to no ethanol. If this is indeed the case, then by all means get the premium

Oh, and to answer the second part of your question about motor damage....

Well, you tell me. You really think a harder to ignite, and slower burning fuel is gonna somehow damage your saw by giving it too much power? or rev too high?

 

[marchanna]

^^agreed. Use the octane your engine is designed for. Cetane number is different. It痴 the inverse of octane, and generally speaking, the higher the number, the better. Easier starts are better achieved through 1. Fresh fuel, 2. A good multigrade oil, and 3. Pre-warming the engine.

 

[patrick_g]

Run the octane rating that is called for. Anything above that (again all things being equal), is a total waste of money regardless of what BS anyone tries to sell you on.

A M E N ! !

Luckily we have a plethora of stations that offer alcohol free gas (mostly regular) as well as the blend (2-3 different octanes.) I only own vehicles that run on unleaded regular (NO ALCOHOL) Or Diesel, no exceptions.

I'm starting to see small engines that state they are ok WITH 10% Ethanol but say to avoid the 15% blend.

Patrick

 

[bcp]

You guys are sure bringing back the memories. I was a petroleum lab technician in the Army in the 1960's, specializing in the CFR octane testing engines. I've forgotten almost everything by now, except when someone mentions something like Reid Vapor Testing. I've done it, but darned if I can remember the exact process after 50-60 years.

Bruce

 

[Ortimber]

I do not believe any normal pump gas, regardless of octane rating will hurt any modern engine. Race or aviation fuel, I have no idea.

 

[marchanna]

A higher octane rating won稚 cause damage to your engine. In older engines a lower octane can cause knock, which well documented regardless Ng the damage that can be caused. Most newer engines can electronically adjust the timing to prevent knock, but you will take performance hit.

 

[smstonypoint]

FWIW, Stihl sells an ethanol-free 92 octane premixed fuel (50:1).

Steve

 

[jgayman]

Alot of people are totally idiots when it comes to octane and just what it means.

High octane, all else being equal, will make your saw start HARDER in the winter.

Heh heh... technically true. Folks just assume that higher octane means better, cleaner, faster... I mean... it costs more so it HAS to be better, right? ;-)

Back in the late 80's I bought a new JD 175 Hydro that was miserable to start right from new. I contacted the dealer and their recommendation was to make sure I was running "Hi Test Gas". Ahhh... right. It turns out the choke rod was misadjusted and the engine was only getting half choke.

Around here all grades of gasoline have the same Ethanol content. I run non-Ethanol in all my small engines but unfortunately the only grade available is 91-octane so that's what I use. It costs around $0.50 more per gallon than Ethanol-laced Premium.

 

[jgayman]

FWIW, Stihl sells an ethanol-free 92 octane premixed fuel (50:1).

Steve

Yep - it's close to $30 per gallon. You can also get TruFuel at places like Home Depot for a around $20/gallon.

 

[Gary Fowler]

I can mix a lot of fresh fuel for the difference in cost per gallon of the canned stuff. Even if I pour out 13 gallons of stale fuel, I will still be ahead of the game. The most mixed gas I have ever used in a year is 2 gallons, now it is less than a gallon per year with my occasional saw and weedeater use. If it starts to get stale, I just pour it into my trucks fuel tank and mix up another half-gallon.

 

[Garandman]

Just wondering if high octane fuel (91 and 94 octane) will damage the 2 and 4 cycle motors. We live in a cold climate and was suggested to run high octane fuel in the winter so the motors will start easier.

If you posted your location in your profile you would get more appropriate advice.

We have relatives in S FL who believe Jacksonville is a “cold climate.”

 

[buickanddeere]

Just wondering if high octane fuel (91 and 94 octane) will damage the 2 and 4 cycle motors. We live in a cold climate and was suggested to run high octane fuel in the winter so the motors will start easier.

Not going to damage the engines, in fact is required to prevent detonation, ping and knock. Those holes burned through pistons, burned plug electrodes , broken rings, crushed ring lands, bent rods and failed bearings ain't from a lack of lube oil.
Old fuel that has been sitting looses octane and mixing lube oil with gasoline also lowers the octane rating.
Using premium also avoids ethanol in some regions. Otherwise non ethanol can be sourced at marinas, speciality fuel depots and airports.
For all the little bit of small engine fuel used per year, any "savings" by using the lowest octane fuel is false economy. If another $5-$25 is going to bankrupt your operation, there are other more serious issues to address.

 

[oosik]

A lot of people will believe just about anything - if its said often enough or has slick advertising or both.

 

[Billrog]

A service station here sells premium marked gas for the price of regular and I've been using it in all my small engines for over 10 years now with no ill effects.

 

[Gator6x4]

Stihl recommends a minimum of 89 octane for their 2 Cycles. Or they do on the chainsaw and leaf blower I own.

Gasoline Guidelines for STIHL Outdoor Power Equipment | STIHL USA

 

[Kish318420]

Cold Climate?!? I think you need to come North (Up to the Great Lakes and Plains, or even our Canadian Friends) if you want Cold Climate. Battery Tenders, Block Heaters and Personal heating equipment are required/needed here.:shocked: We just set new low temps for the month of Dec (-16 degrees) that is not wind chill either. We still have Jan and Feb coming up.

 

[fried1765]

Yep - it's close to $30 per gallon. You can also get TruFuel at places like Home Depot for a around $20/gallon.

You can buy 100LL (low lead) gasoline at your local airport for around $6 per gallon.

 

[buickanddeere]

You can buy 100LL (low lead) gasoline at your local airport for around $6 per gallon.

That 100LL is wonderful stuff. Never goes stale from age . Never deteriates plastic, rubber or metal.