# chainsaw fuel: high octane or regular octane?



## Mt Ski Bum

Hi everyone-

What type of fuel do you guys recommend using in my new Stihl 250? I know Stihl says to use premium-octane fuel in all of its chainsaws, but I've also heard that the ethanol found in many high-octane fuels nowdays isn't good for the chainsaw's engine. 

I have a good family friend who has a Poulan Pro saw & he say he uses regular octane fuel in it, & my dad has a Poulan saw at work & he's never used anything but regular-octane fuel in it.

Seeing that they both used regular somewhat assures me that regular's ok for my saw, but I'm still a bit concerned, since Stihl's are higher-end saws than Poulans, & thus might not like being fed regular-octane stuff.

Anyone have any input on this? Thanks!!

EDIT: Cut down my first tree with my 250 today- worked great (besides getting the bar stuck a couple times  :red- the gas in there was whatever the guy at Ace Hardware put in it when I bought it- I forgot to ask what octane gas he used. (oops)


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## Thistle

I've used both regular & high octane for almost 30 yrs & 10% ethanol blend the 10 yrs or so its been around here.Never any problems with the carburetors or other parts.At least one of the saws gets used several hours a week,only time any of them may sit for more than 2 weeks is in the hottest part of summer from mid June to late August,I rarely do any cutting or milling then unless its storm damage or some special job.For those periods the saws sit dry with no gas left in tanks.


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## oldspark

High octane non ethanal is the way to go.


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## ikessky

My FIL was having some issues with his saws a few years ago (professional logger).  He took them into the shop and the mechanic told him to start using premium fuel.  Since he started using it, he's had zero fuel related issues.  That is enough for me to only use premium in all of my small engine equipment.  Plus, our local gas station now only carries ethanol-free premium because of the snowmobiles and four wheelers.


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## smokinj

Hi as I can find!


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## firefighterjake

Short answer . . . probably best to go with what the manufacturer recommends.

Longer answer . . . I used to run the hi test in all my small engines . . . switched over to using regular since everything I own is now out of warranty and honestly I have had no issues what so ever . . . I do use Star Tron fuel stabilizer however on most of the small engines whenever I know I will not be using the equipment for several weeks.


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## RNLA

Not that I hold any secrets or anything but, mix only a gallon if you will be an occasional user. I cut almost everyday, as I run a tree service, I run mid grade 89 octane mixed at the 50:1 that STIHL recomends on the bottle. I only use STIHL 2 cycle oil. I have several friends who have tried other oil or gas combonations for whatever reasons money, power, or something else. They all have come back to the plain vanilla mix of mid grade gas mixed at 50:1 All this being said the company VP that makes race gas and other fuels has a new product called SEF ( small engine fuel ), I would try it if it does not cost much more than what I do now. They also have the gas pre-mixed at 50:1 for use in 2 cycle engines...


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## smokinj

RNLA said:
			
		

> Not that I hold any secrets or anything but, mix only a gallon if you will be an occasional user. I cut almost everyday, as I run a tree service, I run mid grade 89 octane mixed at the 50:1 that STIHL recomends on the bottle. I only use STIHL 2 cycle oil. I have several friends who have tried other oil or gas combonations for whatever reasons money, power, or something else. They all have come back to the plain vanilla mix of mid grade gas mixed at 50:1 All this being said the company VP that makes race gas and other fuels has a new product called SEF ( small engine fuel ), I would try it if it does not cost much more than what I do now. They also have the gas pre-mixed at 50:1 for use in 2 cycle engines...




I bet that racing gas would be big money.....Let me know per gallon price when you get the figures!


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## mayhem

Run what the mfr recommends.  The ethanol content is unrelated because there is the same amount of ethanol in regular, mid grade and premium grades of gas...at least in MA thats how it is.


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## oldspark

mayhem said:
			
		

> Run what the mfr recommends.  The ethanol content is unrelated because there is the same amount of ethanol in regular, mid grade and premium grades of gas...at least in MA thats how it is.


 That is not true for every where though, we have only one grade of gas with ethanol in it here and that is 89, we have non ethanol 87, and 91 or 93 depends on the station.


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## Backwoods Savage

I've run both regular and mid grade and noticed no difference. I also checked with another fellow who does lots more cutting than I do and he has never ran anything other than regular gas in his and he had never heard of using a higher octane. I did kid him a bit for not reading his owner's manual.


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## 3fordasho

I run a premium non-ethanol gas. I think the octane is only 91 which barely makes it "premium".  If you can find it run non-ethanol gas regardless of octane rating.
The ethanol makes the saw run leaner and some of them are set dangerously lean from the factory to meet EPA regulations.  Unfortunately you can only richen them up a little because of the limiter caps.  When out of warranty you can remove the caps and tune to your liking.


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## DanCorcoran

oldspark said:
			
		

> mayhem said:
> 
> 
> 
> 
> Run what the mfr recommends.  The ethanol content is unrelated because there is the same amount of ethanol in regular, mid grade and premium grades of gas...at least in MA thats how it is.
> 
> 
> 
> That is not true for every where though, we have only one grade of gas with ethanol in it here and that is 89, we have non ethanol 87, and 91 or 93 depends on the station.
Click to expand...


That's interesting: Iowa, home of ethanol, lets people in the state buy 3 out of 4 grades without ethanol, while the rest of us are forced to buy it.  Sounds like the politicians and lobbyists in Iowa have done a great job of putting one over on us!


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## RNLA

Jay, the VP product is not necessarily "race gas". It is an ethanol free product made specifically for "small engines". VP's web site just says it is offered in regular and pre-mixed at ratios of 40:1 and 50:1. It has an octane rating of 94 which is 2 points more than pump gas here. I have doubts on the affordability though. I did ask my STIHL dealer and he claims that if a person takes good care of the saws, including the chain, filter, oil ETC. keeping all in good condition he has not noticed any real serious problems with the ethanol gas. He stressed the importance of not letting the saw sit with gas in the tank and not mixing more gas than you can use in a month, storing the fuel in a cool dry place.... :coolsmirk:


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## smokinj

RNLA said:
			
		

> Jay, the VP product is not necessarily "race gas". It is an ethanol free product made specifically for "small engines". VP's web site just says it is offered in regular and pre-mixed at ratios of 40:1 and 50:1. It has an octane rating of 94 which is 2 points more than pump gas here. I have doubts on the affordability though. I did ask my STIHL dealer and he claims that if a person takes good care of the saws, including the chain, filter, oil ETC. keeping all in good condition he has not noticed any real serious problems with the ethanol gas. He stressed the importance of not letting the saw sit with gas in the tank and not mixing more gas than you can use in a month, storing the fuel in a cool dry place.... :coolsmirk:




I hip on the later part. Just thinking of what a gallon would run probally enough to make lol...lol


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## oldspark

DanCorcoran said:
			
		

> oldspark said:
> 
> 
> 
> 
> 
> 
> 
> mayhem said:
> 
> 
> 
> 
> Run what the mfr recommends.  The ethanol content is unrelated because there is the same amount of ethanol in regular, mid grade and premium grades of gas...at least in MA thats how it is.
> 
> 
> 
> That is not true for every where though, we have only one grade of gas with ethanol in it here and that is 89, we have non ethanol 87, and 91 or 93 depends on the station.
> 
> Click to expand...
> 
> 
> That's interesting: Iowa, home of ethanol, lets people in the state buy 3 out of 4 grades without ethanol, while the rest of us are forced to buy it.  Sounds like the politicians and lobbyists in Iowa have done a great job of putting one over on us!
Click to expand...

 Yep I dont understand that either, they tried to cram it down our throats a few years back but I think there were so many complaints they let it go.


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## ikessky

3fordasho said:
			
		

> The ethanol makes the saw run leaner and some of them are set dangerously lean from the factory to meet EPA regulations.  Unfortunately you can only richen them up a little because of the limiter caps.  When out of warranty you can remove the caps and tune to your liking.


  And when you are turning 13,000+ RPMS, it won't take much of a hiccup to wipe out the piston.


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## richg

Gasoline octane drops when it sits in storage, even if you ad stabil. The 89 gas you buy today could be 87 at best in a couple of months. I buy 93 octain, use double the amount of stabil and also add some drygas. Dang cr@p they sell these days has water in it.


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## lobsta1

richg said:
			
		

> Gasoline octane drops when it sits in storage, even if you ad stabil. The 89 gas you buy today could be 87 at best in a couple of months. I buy 93 octain, use double the amount of stabil and also add some drygas. Dang cr@p they sell these days has water in it.



I am assuming you are in an ethanol state in which case ; why are you adding more alcohol? I'm no chemist, but the drygas is probably methanol. As far as I'm concerned, meth, eth, they are still alcohol based.
Al


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## mayhem

oldspark said:
			
		

> mayhem said:
> 
> 
> 
> 
> Run what the mfr recommends.  The ethanol content is unrelated because there is the same amount of ethanol in regular, mid grade and premium grades of gas...at least in MA thats how it is.
> 
> 
> 
> That is not true for every where though, we have only one grade of gas with ethanol in it here and that is 89, we have non ethanol 87, and 91 or 93 depends on the station.
Click to expand...


Thats why I left the disclaimer at the end of my post.  

If non ethanol gas is available, get that, regardless of the octane rating.  If multiple grades of non-ethanol gas are available, use the one that matches your saw manufacturer's octane rating.


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