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87 octane in ms270?

stihl86

stihl86

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"Nothing to do with combustion temperatures"
I guess this is true. No, you don't chose octane according to combustion temps.
(good reason not to overanalyze things. Follow recommendations) But low octane will raise this temperature. So, it does have something to do with combustion temperatures. Preignition/detonation isn't good for an air-cooled engine. And, you never hear it.
 
CausticUC

CausticUC

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So Madsen's is wrong? Just run 87 corn fuel and all is hunky dory! :ices_rofl:
Wrong? I did not say it was wrong, it is just vastly less common.

Sure, lower octane means a dirtier burn and a higher temperature, but you are more likely to run into the problem with a clogged air filter or spark arrestor before it is solely caused by the fuel. There is a reason that aluminum cylinders are coated these days.

... will that stop you from melting a cheap knockoff piston? Personally I do not know, I try not to get unknown knockoffs so usually if I have an issue, pistons fracture first.

.... with exception of the piston that is in my massey; the PO dropped a screw into the cylinder. It now has a screw imprint in the cap and top of the piston.
 
stihl86

stihl86

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A dirtier burn? I think it's just the opposite. Unused octane components and the detergent additives in a "premium" fuel leaves more deposits on piston heads.
 
CausticUC

CausticUC

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A dirtier burn? I think it's just the opposite. Unused octane components and the detergent additives in a "premium" fuel leaves more deposits on piston heads.
Yes, dirtier. The fuel is less refined and less oils and naphtha removed. It contains more oils and paraffin.

In regards to higher octane pump gas, yes those items you mentioned are added in the MON fuel and mixed in to reduce the knocking in multiple cylinder American Designed engines. This is related to the Zinc reduced Oil issue it seems and is one way to compensate for it.

Unfortunately, most fuel is designed for and purchased for the daily driver automotive engine.


Edit:

Before this wanders into insanity; there is a VERY large difference between the designed efficiency of fuel combustion for a specific fuel type and the raw combustion of the same fuel type.

Simple similar examples are Bunker Fuel and Diesel Fuel
Or to go with the still: Vodka and Everclear

Low grade with more natural contaminants vs a higher grade with specific elements added back in.
 
CausticUC

CausticUC

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You claim regular fuel is less refined than premium?
Additive packages designate the grade.
Not the refining.
Of course it is, more refining costs more money. More time, more scrubbing, more equipment. There are many refineries tooled for specific feedstocks and grades.


Petroleum is a huge money game.
 
stihl86

stihl86

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What??? Hey, wait a minute. Is this Rudy?
Or the same base with different additive packages.
That's more cost effective, which is the name of the game
in the oil rackets.
I'm out of this one.
 
CausticUC

CausticUC

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What??? Hey, wait a minute. Is this Rudy?
Or the same base with different additive packages.
That's more cost effective, which is the name of the game
in the oil rackets.
I'm out of this one.
That is only cost effective in small volumes.

A refinery will not fit a 15 million dollar scrubber that they have to refit twice a year if they can sell more in volume for a lower grade with less hassle. There is always a buyer.


Here is a simplified overview: https://www.britannica.com/technology/petroleum-refining/Lubricating-oils
 
farmer steve

farmer steve

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For the record I ran 87 octane E fuel for almost 20 years @ 50:1 NO problems. Stihl 023,MS250 and MS290. All saws Stihl run today. Never blew anything up. Replaced one carb. Just lucky I guess after reading lots of horror stories.
 
MooneyPilot

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87 will be fine. Much more important is whether the gas has ethanol, and how long it'll take you to use it up. If it's got ethanol, you've got a month before it's questionable, less if it's stored somewhere damp. Without ethanol, you might get two months give or take.

He said he’s using HP Ultra. It has additives that make it age well. In any type gasoline. I would run 91 or 93 octane out of the pump with HP Ultra and if the storage were sealed it would run fine a year from now. Before I started using Avgas, I used hi octane 10% ethanol stored in a sealed can for as much as a year with no trouble whatsover. I was told by a guy who had a store with no products beyond Stihl that this would work and it has worked very well.
 
Ryan'smilling

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He said he’s using HP Ultra. It has additives that make it age well. In any type gasoline. I would run 91 or 93 octane out of the pump with HP Ultra and if the storage were sealed it would run fine a year from now. Before I started using Avgas, I used hi octane 10% ethanol stored in a sealed can for as much as a year with no trouble whatsover. I was told by a guy who had a store with no products beyond Stihl that this would work and it has worked very well.

Whatever works for you, man. Personally, I think ultra sucks as oil, and it smells unbelievably awful in the exhaust, so I'd never run it. Have I run ethanol gas more than a month old? Yes, but would I recommend it to someone? No.
 
TnShooter

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Sorry guys, I didn’t mean to make this an argument.

Here is the short point.
I run equipment, I don’t know everything about it, or how it all works.
But try to take care of ALL my equipment.

Now for the longer part.

I have always used the Highest Grade Non-Ethanol fuel I could get in my saws, blowers and trimmer.
It was 93 Octane and was always available.
However, I couldn’t find it today. The place that sells it no longer sales it.
And 87 Non-Ethanol is all I could find

I pretty know how octane works, I ran High Octane in my Supercharged Automotive Engines.
I know what detonation is and have heard it when under High boost in certain situations.
That’s actually what even made me “Question” the 87 fuel.
I don’t know if you’d even hear detonation when running a saw full throttle in a cut?
( I use ear protection too )

I will be be the first to tell you. Yes, I did mess up 3 carbs using Ethanol BEFORE I knew what was causing my issue.
It was a combination of storage and high humidity. I run equipment, I don’t don’t study it. If it breaks I try to repair it.
I have multiple saws, blowers, and trimmer. I take care of a lot of land. I have back ups. And the backups can go a few months between uses.
 
JimmyT

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TnShooter, I guess since Stihl and Husqvarna make 3 grades of saws Homeowners,Farm and Ranch and the Pro saws it might be best to match them up with the 3 octane grades of gas. I thought I did read somewhere that Stihl recommended a min. of 89 octane. In Germany Stihl and Dolmar were designed to run on 100% gas without ethanol. Man I really would hate to drop $1300 or $1400 on a new MS 500i and end of smoking that baby. Shooter after all this conflict I need a week in Gatlinburg.
 
CausticUC

CausticUC

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"In an effort to meet federal renewable fuel standards, higher ethanol blends are being brought to market. Ethanol is an oxygenated fuel. Engines designed for up to 10% ethanol may have problems with fuel higher than 10%, including engine failure. When a small number of retail gas stations in select U.S. states began offering E15 and higher ethanol blends for sale in 2012, we at STIHL grew concerned. We want to protect our customers and future customers from inadvertently damaging their equipment by using the wrong fuel.

Most people believe any fuel sold at a gas station or other retail fuel station is likely legal and safe for any engine product. This is not true, and STIHL owners need to become aware of the fuel for which their equipment was designed, built and warranted – and use only that fuel."

 
Harmon

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Many good points being made here. Running good fuel instead of spending time and money diagnosing fuel related issues is worth it to me. That being said when I get fuel I often wonder "is this fuel they are selling me really 90 octane ethanol free? how would a guy know?" Someone that sold me an 038 once gave me an ethanol test kit with the saw - maybe I paid too much and he wanted to make up for it - I never used it. Saw ran great, though. This was down in Illinois too, where they really do have too much corn.

Somewhat to the side, this spring when we were going back to work in the beginnings of a pandemic (tree services were deemed essential in Anchorage) we were also experiencing some pretty low fuel prices ($2.75 down from $3.50 something!) so the boss decided to stock up on 90 octane ethanol free. He got 5 55 gallon drums at the yard filled up by the local fuel company we get diesel from, stuck a hand pump in one of them and slid the locker with all the 2 cycle mix and bar oil over by it. Coming out of three months of hibernation or winter jobs as we do, no one noticed the first jug of mix was pretty smoky. The next one was real smoky and the new guy got yelled at and lectured some about the importance of mix ratios. Myself and another fellow with years of experience very carefully mixed the next, it was real smoky too. After work that day asked the boss where he got the barrels - "oh i hauled some diesel in them when i brought my boat up last summer..." It didnt seem like enough diesel to make that much of a difference but the next day when the foreman called the fuel company and found out they don't sell gasoline products nor have a truck dedicated to that we all had a real good belly laugh and were not bothered much by mosquitoes at all.

still not sure what that fuel blend was, and I only melted one spark plug that summer.
 
CausticUC

CausticUC

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Being Anchorage, you know it's likely a mix of boat fuel, aviation, bunker and whatever collected in the tanks. The warning is to never run your tanks dry! Same warning goes for the Yukon.

Alsska the land of the marine highway and the last stop before Russia!
 
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