# Racing/High Octane/Aviation Fuel in Chainsaws?



## Hexa Fox (Mar 24, 2014)

First off please no one jump on me and call me a moron, I would appreciate it. Okay I really want this cleared up. I know very little about fuel except Gasoline can be used to get harsh chemicals off your fingers and Diesel Gels up when it gets cold. So I have a lot to learn to say the least. 

A couple years ago or so I came here (I think) when I was having trouble with my MS 290 Farm Boss not starting at all. I came to find out that it was the crappy ethanol-free fuel the dealer directed me to use in it. I came to find out that the non-ethanol fuel was garbage in the saw. This was also due to us (Charles Town, WV) not having any high rated ethanol free fuel available. Plus I figured out that since no one ever uses it that it sits in the tank and degrades to be even worse. Therefore I was having major issues with my saw.

Long story short I took it under warranty to a real authorized Stihl Dealer and he told me he didn't care what anyone else told me. He then told me to buy the highest rated fuel I could find which is around 94 here around Charles Town, WV. This instantaneously resolved my issue and the saw has been starting right up. However this recently got me thinking and reading.

Is it okay to use any kind of Racing Fuel, Aviation Fuel, or other High End Fuel in Chainsaws? This has been a HUGE argument forever and everyone is back and forth. People say they burn cooler then they say that they burn hot. Then they say that it is all loggers use in their saws and others saw only if you want to blow up the small engine. Although it would seem that there are more people saying if you can afford it buy the Racing Fuel, Aviation Fuel, etc that it is the way to go. Just I really can not afford to have my saw explode in my hands or do damage to it overtime. 

It is time for me to go get some new fuel and is why I have made this post. I am considering driving out to Summit Point Raceway and buying some Racing Fuel to try it out. Please give me your thoughts and advice. I can afford the fuel, especially if it will help my saw in the long run and give me a longer shelf life.


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## windthrown (Mar 24, 2014)

I avoid racing fuel and I would never run Avgas in my stock chainsaws. Avgas has lead in it, and that is highly toxic at any level. Also 100 octane is a waste in a stock chainsaw designed and tuned to run 89/90 octane gas (US rated). The ignition and compression are set to run mid-grade US gas on most saws. You are better off with E0 non-ethanol gas, because ethanol picks up water over time. E10 will run OK, and if I had my choice between regular E0 gas and supreme E10 gas, I would probably run supreme E10, but with a good gas stabilizer in it. In any case, avoid using old gas in a saw. If you had a higher compression chainsaw, or a highly modified chainsaw with the timing advanced significantly, then higher octane racing gas might make sense. A stock MS290 is neither. I would save your money on the spendy racing gas and buy a brand name supreme E0 gas. Travel for it if you have to, I used to go up to WA state to get mine. Also use a high quality 100% synthetic premix oil with a JASO FC or FD rating and good gas stabilizer like StaBil, StarTron or SeaFoam.

I use E0 supreme 92 octane gas with StaBil red gas stabilizer in it. Reason being is that gas drops in octane fast and stabilizers will keep the octane value up for a year or two (depending on how much you add). If you buy 92 octane gas it is likely going to test out at about 90 by the time you get it into a gas can and add stabilizer to it. When you add premix oil to your gas you also lower the octane further by a few points (depends on the amount that you add, I use 45:1 gas/oil in my later model stock saws, and 40:1 in my older and modified saws).

My ex insists on using regular E10 gas in her MS290 saw. She says if it is good enough for the county work crews, it is good enough for her. I do not agree, but her 290 is still running strong after about 8 years of use. She uses fresh gas though with stabilizer and air-cooled premix oil (avoid generic and TCW-3 rated oil) in it and not stuff that has been sitting in a can down in the barn for who knows how long. She also keeps the saw tuned which is important so that you do not run it lean and burn up the engine.


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## Hexa Fox (Mar 24, 2014)

Thanks for your reply windthrown. I use the top grade Stihl Ultra "Stabil" stuff they recommend. The ethanol free stuff made no difference what I did it was just garbage. I found this website a while back. 
http://pure-gas.org/?stateprov=OR

You can look up the nearest places to you and I have absolutely none besides the Liberty Station which only sells 87 Ethanol Free. I know 100% this stuff is my problem so if I am going to go with Ethanol Free I am going to have to buy it somewhere else with a better rating. I am on the Panhandle of WV so I surround a lot of other states and the site wants you to search by state so it is a little counter productive for me. Maybe you could take a look at tell me exactly what I should be looking for?

Also about the MS 290. I am basically the "NAK" (Neighborhood Arborist Kid) and I am getting ready to invest in a MS 660 Magnum with a 28" Bar. I honestly can't wait!


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## CR888 (Mar 24, 2014)

Good post above and the only thing l could add as l am no fuel expert by any means is that l find all my gear prefers the standard E-free 91 unleaded. Fresh fuel is a must IMO. My saws don't run as well with the premiun high octane stuff. Also the turnover is a lot higher on standard 91 than premiun thus fresher fuel. We get good fuel here though. l too would forget 'race' fuels on stock saws. Engineers design *** around standard 87-91 octane not race fuel or premium. Higher octane fuels probably need higher compression engines to take advantage of it. Understanding detonation enviels this.


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## windthrown (Mar 24, 2014)

I get premium E0 gas because that is the _only_ E0 gas that you can get in OR and WA now. My saws run better on it, and I ran premium gas in my saws before E10 came along anyway. I found that my saws all picked up revs after switching from dyno to full synthetic oil as well. Also note that there is 4% more energy in pure gas than E10 gas (ethanol has less energy than gasoline does).

Also: whatever you run, re-tune your saw carbs after switching between gas/oil types. It will make a difference.


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## windthrown (Mar 24, 2014)

Using the Pure Gas web site, you certainly do live in the E0 higher octane desert. All the E0 anywhere near you is 87 octane. Not even mid grade E0 is anywhere close in PA, VA, MD or WV. That sux....


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## jimrb (Mar 24, 2014)

Isn't midgrade fuel at many stations a blend of high test and low test? Point I am making is at my stations the premium fuel is really that stale, just might not be sold as much as the lowest grade. My car and truck are diesel so I can't buy midgrade to watch the pump counters spin at the pump. If you look closely you will see 2 or three counters. One for diesel and the other two for low and high test gas.

I happen to use high test (92 octane) for my lawn mowers and 2 cycle engines in hopes that it might be ethanol free. I can start my engines after they have sat for a few months. No signs of ethanol corrosion, which I guess is more water corrosion, yet.


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## Hexa Fox (Mar 24, 2014)

windthrown said:


> Using the Pure Gas web site, you certainly do live in the E0 higher octane desert. All the E0 anywhere near you is 87 octane. Not even mid grade E0 is anywhere close in PA, VA, MD or WV. That sux....


So if I can ask what would you do if you were me? Because I sure can't afford a can of $10.00 MotoMix every time I go to work. Should I shoot for the Racing Fuel? It will stay good longer right even though it probably has Ethanol in it or rather something else?


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## windthrown (Mar 25, 2014)

I would use premium E10 with stabilizer in it. I used it in my saws for a year here when that was all could get. Racing fuel will not do you any better and it is a lot more expensive. Just keep the gas dry and away from water, as ethanol likes to suck up water. Any slosh of water in the gas can and it is toast, even with stabilizer in it.

You could also do a blend of 87 E0 regular and 91 E10 super, and make your own low ethanol E5 89 mid grade. I do not know what your E10 gas really is. It may not be that bad. In California it was 6% last I was there. Here it is full 10% ethanol, the max allowed. Frikke'n Oregon used to be all pure gas until the greenies went wild. Washington held out for another year, and then they rolled to E6 and then full E10. Then the marine engines started blowing up left and right, and they screamed bloody murder. So the state passed an exemption allowing premium E0 gas, and it is sold at more places here now, but for a 15% premium. For plain gas...


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## windthrown (Mar 25, 2014)

jimrb said:


> Isn't midgrade fuel at many stations a blend of high test and low test?


 
Here in the west mid grade comes from the refinery blended that way. We get all our gas from Washington state in Oregon, as there are no refineries here. Lots of super and turbo charged auto engines require premium now, so it sells more than it used to. As for gas getting older in the station tanks, it is fresher at stations that do more business. For that reason I get my E0 gas at a busy station that gets 2 trucks of gas a week. I avoid mom and pop places out in the boonies that do not get as many deliveries. Also US gas is rated as an average of refinery fresh and pumped into your car. So it is already dropped in octane by the time you pump it, regardless.


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## mdavlee (Mar 25, 2014)

I use 87 in modded saws with no ill effects. If you have e free 87 use it instead.


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## Hexa Fox (Mar 25, 2014)

mdavlee said:


> I use 87 in modded saws with no ill effects. If you have e free 87 use it instead.


We just got done talking about that. The only ethanol free stuff over here comes from a station called Liberty Station and it is 87 but my chainsaw won't run on it on account of how badly degraded it is. Then as windthrown just pointed out I have no place near me that even sells half decent ethanol free. This is probably why my nearest certified Stihl Mechanic told me to find the highest grade, freshest stuff possible and go with that. As we really do not have a choice. Either that or MotoMix. Which is why I am considering just going out and buying the Racing Fuel. Even if it helps a little bit it will be worth it. Especially if it is fresh and can sit for a little while.

This is probably my main problem though because as windthrown pointed out the ethanol can absorb moisture over time. Another reason my Stihl Mechanic told me to dump it out after every three months at a minimum. My neighbors around here buy nothing but Stihl and they use gas mix that is years old and have absolutely no trouble. People told me nothing good can come out of using fuel that bad but so far I haven't heard any of them say they are having trouble with their saw. I am was the only one and it was when I used that crappy 87 ethanol free stuff. 

As soon as I put that garbage in my saw and start it and it works whatever other gas it had in it before out and starts on the ethanol free stuff it immediately dies. I'm also talking fresh stuff that I just got from the pump hours before putting it in my saw. Then it will not start at all after that. I honestly no lie think I could put beer in it and it would run longer and better.


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## Hexa Fox (Mar 25, 2014)

Long story short that garbage will kill my saw long before the moisture in the ethanol does. From the way things look I do not have a choice but to try to find fresh premium grade fuel either.


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## Hexa Fox (Mar 25, 2014)

I wish MotoMix was affordable but for some of the operations I might be taking in this year it certainly is not. Especially when I pick up my MS 660.


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## mdavlee (Mar 25, 2014)

Have you tried to retune it for that fuel? If you get racing fuel you're going to be way rich and will need to retune to get it to run right. VP gas in 5 gallon pails would be your best bet. It will last a year in a cool place.


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## Hexa Fox (Mar 26, 2014)

mdavlee said:


> Have you tried to retune it for that fuel? If you get racing fuel you're going to be way rich and will need to retune to get it to run right. VP gas in 5 gallon pails would be your best bet. It will last a year in a cool place.


Sadly I do not know the first thing about tuning a chainsaw. Is it tough? How would I know how to tune it for a specific fuel?


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## Hexa Fox (Mar 26, 2014)

mdavlee said:


> Have you tried to retune it for that fuel? If you get racing fuel you're going to be way rich and will need to retune to get it to run right. VP gas in 5 gallon pails would be your best bet. It will last a year in a cool place.


I just did some research after I read what you wrote again and came across this. 
http://www.vp-sef.com/index.php/products/pro-max

Good advice mdavlee. I looked up a dealer and there is one close enough. I might have just found my alternative. However would I still need to tune my saw or make adjustments for it to run on that stuff there in the link?


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## mdavlee (Mar 26, 2014)

Hexa Fox said:


> I just did some research after I read what you wrote again and came across this.
> http://www.vp-sef.com/index.php/products/pro-max
> 
> Good advice mdavlee. I looked up a dealer and there is one close enough. I might have just found my alternative. However would I still need to tune my saw or make adjustments for it to run on that stuff there in the link?



Madsens has a good link for carb tuning or you could pick up a tach and use it. More than likely the saws will be a little rich on that fuel.


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## groundup (Mar 26, 2014)

I too am in the "e free desert"

I have an airport close by and run av gas. I have been running it for awhile mixed 45 to 1 with Stihl synthetic. I am running my 660 on stock settings and its running a little rich which is fine with me. The other saws I have been running on it are self tuning so no issue there.

I contacted Stihl regarding running it, they said don't run it because of the high octane. I use ethanol 92 octane when milling but buy it one day and use it up the same day

I find the saws run cooler using av gas.


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## groundup (Mar 26, 2014)

> Madsens has a good link for carb tuning or you could pick up a tach and use it. More than likely the saws will be a little rich on that fuel



You really should get a tach and/or learn to tune by ear. You'll burn a poorly tuned saw up quicker than one running ethanol gas.


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## Hexa Fox (Mar 26, 2014)

I am thinking about buying this stuff here.
http://www.sears.com/shc/s/p_10153_12605_07189738000P

It is ethanol free 94 grade fuel pre-mixed 50:1 and looks like pretty good stuff... Just $50.00 for 2 gallons is still a little steep. However I have a rewards program with them and have a lot of points as I just purchased a zero turn tractor with them. The only difference is my saw calls for 89 ethanol free. Which means this stuff is still a little rich but think it will work out.


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## Hexa Fox (Mar 27, 2014)

http://www.sears.com/shc/s/p_10153_12605_07189738000P
This stuff is still a little rich but do you guys think it will run in my saw okay without any modification?


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## VA-Sawyer (Mar 27, 2014)

Octane rating does not make a saw run rich or lean. Adding alcohol will make it lean, the more you add, the leaner it gets. This is because alcohol doesn't flow through a given size orifice as easily as gasoline will. It is compounded by the fact that the alcohol brings some of its own oxygen needed for combustion. That leaves more oxygen for the gasoline to burn which is a leaner situation.


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## KenJax Tree (Mar 27, 2014)

Get some VP T4 its $60 for 5 gallons here. Its E free 93 octane and you can mix any oil you want in it.


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## VA-Sawyer (Mar 27, 2014)

That is only $3.00 per Qt.


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## Hexa Fox (Mar 27, 2014)

KenJax Tree said:


> Get some VP T4 its $60 for 5 gallons here. Its E free 93 octane and you can mix any oil you want in it.
> 
> 
> Sent from my iPhone using Tapatalk



Thanks I will take a look at it. Like I said I have reward points from Sears so if the stuff on the link I just posted works okay I am going to buy that and get it shipped to my front door for under $30.00.


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## rw48 (Mar 30, 2014)

What about white gas. Like Coleman in a gallon can. Someone told me it works good in lawnmowers and is more pure.


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## TC262 (Apr 1, 2014)

Find a small local airport and run av gas. It's high quality fuel and has a great shelf life. It's designed to run in aircooled engines like your chainsaw. That's why it's still leaded, to help it run cooler.


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## Black Dogg (Apr 1, 2014)

When I took the chainsaw course for my logger cert. the instructor told us the best additive for keeping ethanol suspended was "Mechanic in a bottle". It's made for freeing stuck engines and for cleaning up poor running ones from what I understand. I've been using it in all my chainsaws and have noticed marked improvement in power and I also seem to get more cutting done per tank of fuel. The biggest improvement, however, has been in my tractor (an old Satoh Bison) which had a seriuos idle problem no matter how much I played with the carb. Added some MIAB and it's been idling and starting like a champ ever since.
You can buy the stuff at Home Depot, right where all the fuel additives are. I went online and bought a quart size bottle after I found out how good it works. Very economical too, by the way: For regular maintenance you only need one ounce for 5 Gallons.


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## VA-Sawyer (Apr 1, 2014)

TC262 said:


> Find a small local airport and run av gas. It's high quality fuel and has a great shelf life. It's designed to run in aircooled engines like your chainsaw. That's why it's still leaded, to help it run cooler.


Sorry, but that just isn't true. The lead is there to raise the Octane rating. It prevents detonation. It does not aid in cooling. Besides the environmental problems with the tetraethyl lead, it can cause plug fouling problems.


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## KenJax Tree (Apr 1, 2014)

Lead also acts as a lubricant


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## VA-Sawyer (Apr 1, 2014)

The lead in gasoline is a lead salt, not metallic lead. It isn't needed to lubricate anything in aircraft engines. A large number of low compression airplane engines are approved to run on unleaded auto fuel.


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## windthrown (Apr 1, 2014)

There are more myths and BS on this thread than I can keep up with. Which is typical when it comes to gasoline...


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## VA-Sawyer (Apr 1, 2014)

Such as?


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## crotchclimber (Apr 1, 2014)

rw48 said:


> What about white gas. Like Coleman in a gallon can. Someone told me it works good in lawnmowers and is more pure.


White gas stove fuel has an octane rating of about 53 from what I've read online. Not recommended for high compression chainsaw engines!


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## VA-Sawyer (Apr 1, 2014)

People think that the lead lubricated the valves, that isn't quite how it worked. The TEL deposits acted as a coating that kept the valve from welding to the seat every time it closed. When the TEL was removed, the valve would form a miniature weld with the seat. When the cam opened the valve the next time, that weld would tear, leaving a divot on the seat. Over time, the seats would have a very rough surface all the way around. The fix for that was hardened seats. They were made of materials that resisted the welding effect.


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## groundup (Apr 1, 2014)

So here it is from the FAA themselves https://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=14754

The lead is used to maintain octane


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## groundup (Apr 1, 2014)

http://www.arboristsite.com/community/threads/avgas-negatives.191031/page-3

Good discussion on the topic


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## mdavlee (Apr 1, 2014)

Alcohol has less energy and an alky carb as to be drilled out. Now nitro added to it doesn't take as much fuel. The higher octane fuel will be richer. Tune the saw to a spec with normal pump gas and then drain it and try canned fuel. The rpm will be a little lower with the richer fuel. Seen it a few times with using canned full for storage when trying to run it later on.


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## Gologit (Apr 1, 2014)

windthrown said:


> There are more myths and BS on this thread than I can keep up with. Which is typical when it comes to gasoline...



True. That reminds me, I need to stop by the airport tomorrow and stock up on 100LL.


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## Hexa Fox (Apr 2, 2014)

windthrown said:


> There are more myths and BS on this thread than I can keep up with. Which is typical when it comes to gasoline...


Yep this is exactly while I made this discussion. Because I need a solution. However I just bought this stuff here.
http://www.sears.com/shc/s/p_10153_12605_07189738000P
I paid $20.00 for it shipped to my front door. I bought a zero turn from them and got a crap ton of points. So I just redeemed them. I am going to get this stuff and hope for the best. Then I may personally call VP and get some pure gasoline sent here and mix it with the Ultra Stihl Oil next time. Because this stuff is rather expensive if you have to pay full price.


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## windthrown (Apr 2, 2014)

I got some of that premix stuff at a GTG for free here a few years ago. Spendy stuff. It ran good though. In a place like you live, I would certainly look for an alternative to what is available.


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## Hexa Fox (Apr 2, 2014)

windthrown said:


> I got some of that premix stuff at a GTG for free here a few years ago. Spendy stuff. It ran good though. In a place like you live, I would certainly look for an alternative to what is available.


Yeah definitely some other gentleman posted here and told me to look into a specific type of VP that is free of Ethanol. I can't remember who it was but if this works out I will probably try to order some of that stuff. It sounded pretty good because it is pure gasoline and you can add Stihl's own recommended oil. So that might be the way to do. 

I just hope this stuff runs good. The octane rating is still a little high for what mine calls for but I think it will be fine as long as this is quality stuff.


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## windthrown (Apr 2, 2014)

Well, you can always lower the octane by mixing it with your E0 regular there. Of course, who knows what else is in that gas... before E10 hit this state gas quality was all over the map. Also CA had that MTBE crap in their gas that has since been banned nationally.


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## rw48 (Apr 3, 2014)

I would like to hear more on additives like mechanic in a bottle. We can't always choose what gas we can buy and can we always trust that the premium is what they say it is. I agree with getting the freshest gas. But what additives are best to keep it going? What about the ethanol treatments? Do they help? What about synthetic oils? Several threads say that is the best and it is what I try to ge


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## KenJax Tree (Apr 3, 2014)

Hexa Fox said:


> Yeah definitely some other gentleman posted here and told me to look into a specific type of VP that is free of Ethanol. I can't remember who it was but if this works out I will probably try to order some of that stuff. It sounded pretty good because it is pure gasoline and you can add Stihl's own recommended oil. So that might be the way to do.
> 
> I just hope this stuff runs good. The octane rating is still a little high for what mine calls for but I think it will be fine as long as this is quality stuff.


I think that was me and the fuel was VP T4.


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## Hexa Fox (Apr 3, 2014)

KenJax Tree said:


> I think that was me and the fuel was VP T4.
> 
> 
> Sent from my iPhone using Tapatalk


Okay thanks KenJax. After I run out of above said stuff that is on the way I will call VP Customer Service (which is great Customer Service by the way) and see if I can order some of that stuff. Then I will mix in the recommended Stihl HP Ultra Synthetic Oil and hopefully be able to go on with my life. For the record I knew that there was going to be a lot of different advice. So I knew from the beginning that (no offense) I would have to pick and choose what I thought was good advice from bad advice. I appreciate everyone's help and input here. I just think if this VP Racing Fuel works out it is going to be the way to go from now on.


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## Gologit (Apr 3, 2014)

Hexa Fox said:


> So I knew from the beginning that (no offense) I would have to pick and choose what I thought was good advice from bad advice. I appreciate everyone's help and input here.



Okay, sorry about my suggestion to use av-gas. It was obviously "bad advice" according to you...although well intended.
I think I'll keep using av-gas, though. After ten years of constant use in a professional setting and no gas-related saw problems I don't see any need to switch. It's not the answer for everybody but I've had excellent service from it.
Good luck with your canned gas.


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## Hexa Fox (Apr 3, 2014)

Gologit said:


> Okay, sorry about my suggestion to use av-gas. It was obviously "bad advice" according to you...although well intended.
> I think I'll keep using av-gas, though. After ten years of constant use in a professional setting and no gas-related saw problems I don't see any need to switch. It's not the answer for everybody but I've had excellent service from it.
> Good luck with your canned gas.



I never said your idea was bad. Actually if the VP Racing Fuel doesn't work the next thing I will look is AV-Gas as you are not the only one that has recommended it. The only reason I was asking a lot of questions about actual Racing Gas is because we have a Raceway not far from where I live. So that would definitely be an option. However I know there is a small public and military use airport near me as well. Whether they will let me buy fuel from them I don't know. Someone told me before that going to some Air Ports to buy a few gallons of their fuel will get you laughed off their property.


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## Hexa Fox (Apr 3, 2014)

Hexa Fox said:


> However I know there is a small public and military use airport near me as well. Whether they will let me buy fuel from them I don't know. Someone told me before that going to some Air Ports to buy a few gallons of their fuel will get you laughed off their property.


I can see it in the newspaper now. "Local Arborist drives forty-five minutes to buy AV-Gas to run in equipment, airport personnel take it as a joke, Arborist strangles multiple airport personnel before pumping five gallons of AV-Gas into container leaving, and later being shot on site for having dangerous weapon (chainsaw) in hands".


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## HuskStihl (Apr 3, 2014)

My apologies for the following opinionated offensive post. Stock chainsaws are not fancy animals. Giving them fancy gas and exotic additives is strictly for the saws owner, not the saw. If I remember correctly, mastermind runs and tunes all his ported saws on 87 octane with no problems. Chadiham tested different fuel on his chainsaw dyno and found (not surprisingly) that regular produced the most power. Modern saw components are designed to see 10% ethanol. The only real issue with E10 is you can't let it sit around exposed to air (but you really shouldn't do that with efree either). Fresh pump gas properly mixed with quality synthetic oil will make your saw happy.
I really wish people wouldn't use the aviation gas. Lead is **** for the environment and our bodies. No saws are designed to run on it, and although nothing bad will happen to the saw if you use it, it will make less power.
My apologies, HS out


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## Trx250r180 (Apr 3, 2014)

what problems are people having with ethonol in the gas ? i think it says 10% on the pumps i get it at ,saws cut wood fine with it ,i store the saws with fuel ,rubber parts are fine too


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## Hexa Fox (Apr 3, 2014)

HuskStihl said:


> My apologies for the following opinionated offensive post. Stock chainsaws are not fancy animals. Giving them fancy gas and exotic additives is strictly for the saws owner, not the saw. If I remember correctly, mastermind runs and tunes all his ported saws on 87 octane with no problems. Chadiham tested different fuel on his chainsaw dyno and found (not surprisingly) that regular produced the most power. Modern saw components are designed to see 10% ethanol. The only real issue with E10 is you can't let it sit around exposed to air (but you really shouldn't do that with efree either). Fresh pump gas properly mixed with quality synthetic oil will make your saw happy.
> I really wish people wouldn't use the aviation gas. Lead is **** for the environment and our bodies. No saws are designed to run on it, and although nothing bad will happen to the saw if you use it, it will make less power.
> My apologies, HS out





Trx250r180 said:


> what problems are people having with ethonol in the gas ? i think it says 10% on the pumps i get it at ,saws cut wood fine with it ,i store the saws with fuel ,rubber parts are fine too



I have heard several times over that as long as you are getting fresh gas (and know it) you can use the Ethanol. Most of our country only uses 10% or at least that is what they advertise. It is just the problem that you can not let the Ethanol sit around in your saw. The "Fancy Stuff" I just bought is ethanol free and is premixed with gas, oil, and stabilizer. So I can let it sit for as long as I want. So if I am out cutting a lot I will probably just buy normal old gas for know as long as I know I am using it. Then if I think things are slowly down I am going to use the premixed stuff I just bought when things start slowing down. So that I have very good premium fuel in the tank and hoses when I got back to use the saw. 

I have never done any dyno nor any power test on saws but my saw is definitely more responsive when I use MotoMix or 94 Octane in it. All I know is you are not suppose to use Ethanol in any of the smaller engines under any circumstances and they tell you that it voids your warranty if you do. Chadiham would not be using the 87 Ethanol free stuff you buy around here either. It sits forever without anyone using it so it is garbage by the time you pump it. 

Anyway it was just like I said before you do not know how old gas is so you are better off getting it from a gas station that gets a lot of action at the pumps. Because I was told this gas goes bad in almost exactly three-four months. Now you have to add in the time that it sits before it is added into the truck for transport, then how long it stays in that truck, then how long it stays in the tank where you are going to buy it. So buy the time you get your fuel and get it home you could be looking at fuel that you only have a month to use or possibly less. Therefore the answer to this is to just not use anything else other than Ethanol free. 

By the way if I understand this right storing your small engine equipment with Ethanol in it is the worse thing you can do. I think because it holds water after awhile? So even though you start it I guess you are forcing your saw to burn a little moisture.


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## Hexa Fox (Apr 3, 2014)

That is just the way I understand it. I am the guy that made this post here asking for information. I also found a few answers as well. Just like I said before my saw calls for a octane rating of 89 that is Ethanol Free mixed 50:1 with oil and gas. I also think this goes for every small engine Stihl makes. Now the problem is finding 89 that is free of Ethanol that is fresh.


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## windthrown (Apr 3, 2014)

A general reply to lots of posts in this thread:

Ethanol in marine 2-stroke engines here in the PNW has caused all kinds of problems. Also if you get any water in ethanol gas, it will mix wit the ethanol and phase separate, whereas in E0 gas the water just goes to the bottom. Ethanol will also extract a lot more water from the air around it, whereas gas will not. Ethanol is also harder on rubber parts and aluminum engines. Give it time, or use it in an engine not designed for it and it will be worse. I avoid E10 in my 2-strokes if I can, but by all means, use it if you like it. 10% ethanol in gas is the maximum that any saw company will warranty though.

As for Mastermind running regular gas (if that is indeed the case) I believe that is a huge mistake, especially given the fact that he increases the compression on his saws with his cut squish mods and he commonly advances the ignition timing. The reason they came up with supreme gas was to avoid detonation/pre-ignition/ping/knock/flaring in higher compression gasoline engines, as well as running engines at high altitudes (which is why AvGas is still used in airplanes). Increasing the compression in a saw _will_ (not might, it simply will) increase the likelihood of detonation. Detonation will cause pitting damage around the squish band of the piston and cylinder, and uneven flaring can and will cause uneven down-pressure on pistons and cause them to tilt slightly. That can cause piston skirt and cylinder scuffing, or a ring catching a port. Maybe a dyno does not care about detonation, but your saw and your wallet eventually will. If you wanna run regular in your ported and modified saws, go ahead. Not in my stock or modified saws though, thanks.

Most all 'good' chainsaws are designed to run mid-grade 89 octane gas (not talking Chicom here). Octane starts to drop as soon as it leaves the refinery. By it has reached the gas station mid grade gas is likely down to 87, and by the time you put it into a gas can and store it for a while, it will be down to 85 or even less. Add premix oil at 50:1 and the octane drops another 2 points, or 3-4 points if you run oil at 32:1 So now you are down to 83 octane or less. Give it time and the octane will sink farther into the 70s to the point where it becomes _bad gas_. That is where the gas starts to flare and detonate badly and does damage to the engine. For that reason I add stabilizer to my gas. Stabilizers like StaBil and SeaFoam will keep octane as high as when you added it to the gas for up to 2 years. It cannot boost old gas octane though. Stabilizers will also help keep the ethanol in E10 gas from phase separating, but only to a point. So I add StaBil red formula to my E0 premium gas right at the station when I fill the gas jugs. My ex insists that regular untreated gas is fine for her saws, because the county work crews use it in their saws. I prefer not to sink to the level of the government myself.

Now there is the case of the opposite here, using LL100 or AvGas. There are several issues with this gas, one being the lead in there. The oil companies originally dumped lead into gas as a cheap way to raise octane, and they made a lot of money off if it. They knew it was highly toxic, and there were many deaths at refineries over the years as a result. Large companies are greedy though, and have no regard for human life. Just look at GM's decision to not replace a 59 cent spring in their ignition systems. At any rate, TEL is highly toxic. Lead smells good and tastes sweet, which is a bane to humans, because it causes havoc with your nervous system. Breathing lead fumes will affect your brain and lower your IQ, lower your motor function, and diminish your senses. The reason they banned lead in auto gas was the fact that the LA CHP officers had an average of half the lethal levels of lead in their bloodstream. The average American had 2-10% of the lethal lead levels in their bloodstream. Since banning it, the bloodstream lead levels have all gone way down, and the relative heath of the average American has gone up as a result. You would be well advised not to run leaded gas where you breathe the fumes. The other thing about lead in the gas is that it can foul your low end bearings, as well as your spark plugs. While lead was used as a lubricant in the valve train in pushrod engines, saws are designed to run lead free gas where the added lubricant qualities of lead are not desirable. The other issue with Avgas is the high octane. If you run a saw at high altitude this may well be an advantage, as altitude is another cause of pre-ignition. However, using a premium grade unleaded auto gas would likely be as effective in preventing pre-ignition at altitudes up to 10k feet. If you do use Avgas, please do not run it on my property or near me.


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## HuskStihl (Apr 3, 2014)

We'd need mastermind to comment, but if I am remembering right, he has never had a detonation issue. Obviously extra octane will give you a safety margin. There is very little chance higher octane will improve a saws performance. Saws have fixed ignition (more or less). They don't have a knock sensor to retard or advance timing in response to the combustion chamber dynamics. Applying 4 stroke logic with regards to compression, detonation, flame front propagation etc cannot be linearly extrapolated to a two stroke. That being said, I typically buy 93 e10 (ethanol free is not readily available), put in stabil and h1r and put it in trufuel cans. Stored air tight it has caused me no problems. One of my saws has 230psi compression and a 7 degree timing advance, and was tuned and run by the builder on 89 octane with no issues. The 150psi ms290 should be just fine.


_All STIHL gasoline-powered engines can be used with up to a 10% (E10) blend of ethanol in the gasoline/engine oil mix. We also recommend that if a unit will be left unused for more than 30 days that it be stored "dry." This means emptying the fuel tank and then restarting and letting the unit run until all the fuel is consumed and the engine stops. For maximum performance and engine life expectancy we also recommend using STIHL Ultra 2-cycle engine oil with built-in stabilizer._

From the Stihl USA website


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## windthrown (Apr 3, 2014)

As for some other stuff posted in this thread:

Please do not use Colman fuel in your saw. That is raw gas without any octane additives in it. The octane of that stuff is about 60 at best. It will cause pre-ignition and most certainly cause damage to your saw, your lawn mower, your car, or whatever you run it in. Maybe your neighbor says it is great stuff and runs it in his or her lawn mower, but that is ill advised.

As for other additives like Marvel Mystery oil and other stuff, the people on web sites like PureGas and the like recommend against it. Most do not recommend any gas additives, other than stabilizer and only if the gas is going to be stored for a period of time. Some premix 2-stroke oils have stabilizers in it, but most do not.

As for dynos running saws better with regular, I believe that is erroneous data due to the many variables involved. You would have to be precise as to what gas your are comparing, how old it is, the type and the actual octane in the gas used, and things like the compression and timing advance in the saws tested. Most data that I have read over the years shows that premium gas has slightly more energy than regular and mid grade gas. Ethanol actually has 60% of the energy of pure gasoline, so E10 has 4% less energy than E0 does. Comparatively, the same type of gasoline (E0, E10, E85) will have the same energy to within 2%, regardless of grade. Premium gas is typically thought to have more energy because higher compression and turbocharged engines have more power, but they get their energy from wasted heat energy or from using more gas, with a higher compression engine and a greater timing advance in the ignition.

E10 is a variable and defined differently in most states, and is _up to_ 10% ethanol. In many places E10 is actually 6% ethanol, which was the blend for urban area winter grade gas before E10 became mandated. 6% ethanol is the rate that it is effective for oxygenating gasoline to reduce smog levels. In California MTBE was used for the same reason, but that has since been outlawed because it leaks from gas tanks and contaminated ground water. Because ethanol has less energy it used less oxygen, and in the combustion process it frees up more oxygen, E10 blends will run leaner than pure gasoline. So if you switch between gas types, you will want to re-tune your carbs on your saws, or get an autotune or Mtronic saw that will compensate for different gas used. Which is similar to going up and down in elevation, every 3,000 ft drop is a 10% gain in oxygen. So re-tune your saws if you change more than 1500 ft in elevation since it was tuned.

OK, I am sure people will scream about these two posts now, which is why I avoided posting them. Gas and oil thread have been debated here for eternity, and likely will continue to be. In the end, its whatever floats your boat. Its your saw. Run what you like. My perspective on this is my background being an engineer and studying a lot of energy production systems over the years. I have also been a grease monkey and rebuilt, raced and run a lot of different types if internal combustion engines over the years.


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## Trx250r180 (Apr 3, 2014)

I know a lot of people that log for a living ,i do not think many of them think this hard about the fuel in their saws ,stihl mix and pump gas seems to keep them going for many years


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## windthrown (Apr 3, 2014)

Yah well, this is AS where we argue about anything and everything.

Also if you talk to guys that tear these engines down all the time, they tell another story. Just do a search on Lakeside Andy's posts here on AS about saws and gas and oil used in them. He has posted many times about seeing lots of detonation damage in saws running regular. He also says that any kind of dyno oil in the premix will lead to low ends gunking up.


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## Gologit (Apr 3, 2014)

Hexa Fox said:


> I can see it in the newspaper now. "Local Arborist drives forty-five minutes to buy AV-Gas to run in equipment, airport personnel take it as a joke, Arborist strangles multiple airport personnel before pumping five gallons of AV-Gas into container leaving, and later being shot on site for having dangerous weapon (chainsaw) in hands".



...You might be right. It could happen. The only airport that ever told me no about buying av-gas was Sacramento International and that was probably because they have the usual big-city airport security thing going on. 
The smaller airports, especially the little one-runway mom and pop FBOs will probably be more than glad to sell you as much as you want. Our local airport, and most of them in a fifty mile radius, have self serve pumps, 24 hour access, and a card swipe just like a regular gas station. Most of them have video surveillance but that's common.
The pump might ask you for an N number but anything you enter will be fine. I've used a string of zeros or the N number from a Stearman that was wrecked twenty years ago and never heard anything about it. So far anyway.

I wasn't knocking your choice of fuels. For the occasional user canned gas might be a good way to go. I just got tired of the pump gas variance in octane, E content, and the resulting performance problems. Like I said, av-gas isn't for everyone but it solved a lot of problems for me and I've had darn good luck with it. I can't get away with buying and mixing a gallon at a time. I usually keep a 55 gallon drum full of 100LL and do my mixing in five gallon cans. The only 1 gallon containers are the ones I pack with me in the woods. I have to go with what I already know will work. We have neither the time nor the inclination for experimenting. LOL...you guys can do the testing, we'll stick with our old fashioned ways.

And for HuskStihl and Windthrown...two extremely accomplished guys that I respect very much, as should most people...I'll try to stay downwind of you when I'm cutting. And I'll try real hard to resist the impulse to get my face down in front of the muffler and inhale deeply. That's what Winstons are for.
And as far as lead's effect on mental acuity...the same symptoms show up in old people. I'm not saying you guys aren't right about lead being harmful. It's just that after fifty years of breathing saw exhaust and over six thousand hours of sitting behind radial engines I believe my fading mental and physical abilities might have a few natural causes. Like being old.


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## mdavlee (Apr 3, 2014)

I ran 87 octane in saws with well over 200 lbs of compression with no detonation problems. I did use octane booster f I remember it. A saw is turning over so fast it doesn't seem to matter about the octane as much as larger bore engines.


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## CR888 (Apr 3, 2014)

l very much respect what windthrown has to say, l really do. However in my experiance in rural areas in Ozzyland l find gas stations turn over the regular 89-91 unleaded more than they sell Premium. l have used premium a few times and can say my saws did not like it as much. l may have been imagining things but they seemed to run hotter and not start as easily. We are fortunate to get really good fuel and E10 is only found close to the city and is easily avoidable. l feel for you guys having it in almost all stations...it sucks! Fresh mix is my concern and l try to buy fuel & mix it and use within 3 days. Anything over about a week gets put in the missus little runabout (prolly good for it). Don't use stabil, nothing against it, l just find my saws like the freshest mix possible and gas that is say two weeks old is noticeably worse when starting, smoke, ect.


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## mdavlee (Apr 3, 2014)

Jon did the 288 piston have any pitting on top off it? It was run with 87 the whole time I ran it?


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## HuskStihl (Apr 3, 2014)

mdavlee said:


> Jon did the 288 piston have any pitting on top off it? It was run with 87 the whole time I ran it?


87???? You bastard! If I'd have known you ran a 230psi saw with advanced timing on 87 I never in a million years woulda bought it!!! No, it's fine.

87 octane and 93 octane gasoline both contain/produce 114,000 BTU's per gallon. Only difference is the speed of that burn. Premium burns slower, allowing further advances in timing and compression, but there is no more "energy" in premium, it does not, in and of itself, produce more power, it merely allows one to take advantage of a more highly strung engine better. I said it before, but I lied. I am now done with the "gas thread". I was gonna add a disclaimer for the earlier 100ll comment exempting Gologit. He's the real deal, and can do whatever the **** he wants. I'd be honored to cut downwind from him


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## mdavlee (Apr 3, 2014)

That's a sign for the others that 87 is fine do saw engines. Tremonkey uses 87 also in saws with up to 250 lbs of compression also.


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## Trx250r180 (Apr 3, 2014)

run the green fuel lines in the stihls ,and will not have the ethonol eating rubber problems when fuel sits in them


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## Gologit (Apr 3, 2014)

250 lbs?! I'd probably have to have a kick starter installed.


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## mdavlee (Apr 3, 2014)

Gologit said:


> 250 lbs?! I'd probably have to have a kick starter installed.



Mostly smaller saws. They don't mind the higher compression on the small bores. I did build a 288 with 230 lbs sort of by accident.


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## Trx250r180 (Apr 3, 2014)

got me beat .......... i stihl run pump gas lol


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## HuskStihl (Apr 3, 2014)

mdavlee said:


> Mostly smaller saws. They don't mind the higher compression on the small bores. I did build a 288 with 230 lbs sort of by accident.


And apparently to expose weakness


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## Hexa Fox (Apr 3, 2014)

Trx250r180 said:


> I know a lot of people that log for a living ,i do not think many of them think this hard about the fuel in their saws ,stihl mix and pump gas seems to keep them going for many years





windthrown said:


> Yah well, this is AS where we argue about anything and everything.
> 
> Also if you talk to guys that tear these engines down all the time, they tell another story. Just do a search on Lakeside Andy's posts here on AS about saws and gas and oil used in them. He has posted many times about seeing lots of detonation damage in saws running regular. He also says that any kind of dyno oil in the premix will lead to low ends gunking up.



Not exactly. Like you guys already taught me a lot of loggers tune and mod their own stuff. Plus if you are a "true logger" they probably own several saws and already lived and learned these mistakes and NOW with trail and error they know what works for them. Another reason I made this is because I need to avoid the "trail and error part".


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## Hexa Fox (Apr 4, 2014)

If you have a method that works for your saws and you have been using it a very long time then that is what I wanted people to share with me. Because I know people around here just buy cheap gas mix the oil in with it and use the same mixture for years. I know a lot of their Stihls are 10+ years old and they start right up. I just don't think these newer saws (or anything) is made like they were in the old days. I love my MS 290 and want it to work a really long time. Even more so now that I am getting ready to pick up a MS 660. I really don't need a $1,300 purchase letting me down because of some garbage gas.


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## Snowleopard (Nov 15, 2014)

Trx250r180 said:


> run the green fuel lines in the stihls ,and will not have the ethonol eating rubber problems when fuel s its in them



I'm thinking the ethanol eats Stihl fuel lines even if you don't leave fuel sitting in them. My 029S just got its fourth fuel line replacement this month, and the others have had at least two each. 

I've gotten careful to run the saws dry before quitting on a daily basis, yet I'm Stihl getting fuel lines replaced every 3-4 years. The replacement lines don't seem to last as long as the originals. The dealer/shop(s) tell me "bad gas" is the culprit and sometimes try to sell me the $8 a quart fuel. I've bought some, but it's just too pricey for a real solution. 

What are these "green" fuel lines, and how do i specify them if I'm taking my saw to a dealer shop?


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## BC WetCoast (Nov 15, 2014)

Snowleopard said:


> I'm thinking the ethanol eats Stihl fuel lines even if you don't leave fuel sitting in them. My 029S just got its fourth fuel line replacement this month, and the others have had at least two each.
> 
> I've gotten careful to run the saws dry before quitting on a daily basis, yet I'm Stihl getting fuel lines replaced every 3-4 years. The replacement lines don't seem to last as long as the originals. The dealer/shop(s) tell me "bad gas" is the culprit and sometimes try to sell me the $8 a quart fuel. I've bought some, but it's just too pricey for a real solution.
> 
> What are these "green" fuel lines, and how do i specify them if I'm taking my saw to a dealer shop?



Doing a 15 minute repair with a $7 part every 3-4 years is a major issue? Hopefully you spend more on air and fuel filters.


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## Snowleopard (Nov 15, 2014)

Not a major issue, just irritating. Yeah I probably do spend more $ on filters, but filters by their nature clog, and need to be replaced or cleaned. Fuel lines could be made to last instead of being a profit center for dealers. How popular would a car be that needed new fuel lines that often?


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## flyinghunter (Nov 17, 2014)

Here the only avgas available is 100. Not low lead, it has a great shelf life but does corrode exhausts. At the pumps we have 91, 95 and at some stations 98 octane octane but all of them won't store well. Couple of years ago I starting selling avgas to a guy who has a lot of vintage cars and was tired of stale fuel, he eventually replaced all the fuel in those cars with avgas and says 3 years on they still start fine. Just confirmed what I knew, if you're gonna have anything sit a while avgas is the only way to go.


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## RYNOMAGNUM (Jan 23, 2015)

Since the only non e gas available is 93 around here, that's what I have ran for years. Hp ultra at 50.1 and no problems. 
After reading this thread I might incorporate some red sta-bil to the mix to help keep the octane I'm paying for.


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## Redoakranch (Feb 3, 2015)

AV GAS for me. I used to have rubber issues every year and now none since switching to AV GAS. The saws run richer and with less pop. No I don't need 100 octane or lead but I love that it doesn't go bad or break down rubber. Think of all the people in LA who didn't die of lead poisoning back in the leaded gas days and heavy smog.


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## Redoakranch (Feb 3, 2015)

On the last trip to the airplort the pumps were down so they had me walk through the terminal to the gas truck with my cans empty and then full! I love small town airports!


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