It won't like idle as well or have as good of throttle response. That's been my experience. I'd stick with the pump gas if it were me.
100LL AV Gas, adjust carb necessary?
- Thread starter TommyGun
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It won't like idle as well or have as good of throttle response. That's been my experience. I'd stick with the pump gas if it were me.
Motodeficient
ArboristSite Guru
Sounds good, thanks. I should keep running the 91 though, not 87? I haven't been cutting much until just recently but I think I was running 91 before.
I believe you manual specifies at least 89, and you have a little more compression than stock. I would run premium just to be safe. I think most here do.
Looks like one of my old threads is back from the dead.... I experimented with the 100LL AV fuel for a while with my 455 rancher. Unfortunately It didn't seem to perform all that well even after retuning the carb. I have now found a gas station on the way to the lake of the ozarks that advertises in big letters "alcohol free premium fuel". They are marketing this to the guys filling up their boats on the way to the lake. So I have been driving a bit out of my way to get good fuel, but its worth it to not have to deal with ethanol fuel and also be confident that my fuel will last longer also. Anyhow...I'm not saying to NOT use the 100LL gas... but I don't think I would recommend it if you can find ethanol free gas somewhere else.
No you won't NEED to tweak your carburetors....If its tuned well on pump gas; Ave gas will be fine with a possible small power loss. Might gain back a little of that power lost from the fuel characteristics if you do tweak them but you won't need to.
I do this all the time.....I have access to Ave gas as you can walk in and buy it at the local Airport. I ran it with the same 32:1 mix two stroke oil as well....it just runs cooler and my bet is a little less power. BUT like my motorcycles where I run the same stuff.....you may loose a bit of peek power but under longer term loads the motor doesn't get as hot and therefore maintains the power level it starts with when using the 100LL. ( Ihave a 455 as well) I used 100LL when I was milling with good results.
With Higher Octane fuels, theoretically you can push parameters like compression and ignition timing...even jetting a little closer to the edge. The gamble is you get more of a power gain pushing those mechanical barriers than you loose with the slower more consistent burning fuel. For those reloaders out there...its like using a slower but more consistent burning powder to maximize bullet velocity in consert with a longer barrel.
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100LL does require you to retune your carb, as does race gas.
:agree2: If you don't adjust, the saw will run too rich.
oneoldbanjo
Addicted to ArboristSite
I agree with Andy and Brad - 100LL Avgas does run too rich if your saw is adjusted for pump gas (Mogas). My saws didn't run great on Avgas even after proper adjustment. I didn't notice much difference under power but they never idled very smoothly on Avgas. Using Avgas was a fun experiment for a summer and it smells cool - but it just isn't worth the inconvenience or expense. Currently the only thing I have Avgas in is my emergency generator - which sits a long time between use and does not run all that well on pump gas (but it runs great on Avgas). (The engine was built before ethanol was added to gasoline and the EPA compliant carb is non-adjustable and it runs too lean on ethanol laden pump gas).
Currently I am running "farm fuel" which is 87 Octane without any ethanol added and it is sold to farmers to use in their bulk tanks. I use this fuel in all my equipment and when I run it in my saws I mix it with about 25% Torco race fuel to get the octane rating up a bit.
Yea they might run a bit rich, I tune my saws to be a bit rich anyway (In the saw world about 100-150RPM off spec)..but they run well enough to work with. I ran mine all last weekend and this weekend with 100LL I bought for my Dirt Bike in saws I tuned for regular gas. Been doing this for at least the last 10 years switching back and forth after deciding to not keep two mixes of 2 stroke fuel.
I think the definition of "acceptable" is where we are apart..most more technical types are looking for optimal performance, I'm looking to get a days work done. If the guy puts 100LL in his saw, it will run just fine. If he wants to optimise the performace of course he will have to "tweak" just as you would with any fundemental change in fuel mixes or octane changes....even temperature & humidity changes will require a little tweak at times. In the old days, I would keep a set of jets for different temperature and weather conditions for my smaller bore race bikes (125's)...would gamble in the morning and hope I didn't stick it in the finals late after noon.. when running multiple classes and didn't have time between heats to rejet.
Every saw I had at our last couple of GTG's have run on both 100LL and standard gas depending on whats happening in my Motorcycle life. I run my old KTM420 MC80's on 100LL & 32:1 synthetics of various brands as it runs smoother and cooler with the 100LL have since 1980. (Especially in low speed situations like woods riding in low gears..not a lot of cooling going on with low speed riding) I haven't seen a reason to go back to separate mixes yet... Performance at the GTG's and in the woods might. Just haven't so far. Maybe we will test the "optimal" mix with timed runs in out "Poulan" race we will hold at the next GTG along with testing 3/8 vs the smaller low pro chains. One thing I can say for certain, when I was milling, the saws ran cooler with the 100LL with no loss in time. So I ran it exclusively when I milled.
This brings up the main issue for me when tuning my stuff...duration of work cycle. During a day in the woods, it might start at 50 degrees and end at 85 here in CNY so you would think theoretically you should lean out the saw as the day goes on, right? Also the "work cycle" might be 15-20 seconds per cut in one situation..then 2-3minutes when ripping fence post in another. I want to tune my stuff at the point of where the temperature is at the high side of the typical work cycle so I'm tuning to the worst condition on initial tweaking. AND different mixtures can effect where that steady state high point is. After fiddling with this for years..I ultimately just do plug checks on the first couple of jobs when I setup & learn my saws and look to tune for the lowest common denominator and this ends up being tuned a bit rich. My stuff runs. Once in a while I have to tune a bit to more extreem situations...like when I was cutting in 0 degee winter days...or last week in humid 88 degree days. I just report what I see real time.
I think the definition of "acceptable" is where we are apart..most more technical types are looking for optimal performance, I'm looking to get a days work done. If the guy puts 100LL in his saw, it will run just fine. If he wants to optimise the performace of course he will have to "tweak" just as you would with any fundemental change in fuel mixes or octane changes....even temperature & humidity changes will require a little tweak at times. In the old days, I would keep a set of jets for different temperature and weather conditions for my smaller bore race bikes (125's)...would gamble in the morning and hope I didn't stick it in the finals late after noon.. when running multiple classes and didn't have time between heats to rejet.
Every saw I had at our last couple of GTG's have run on both 100LL and standard gas depending on whats happening in my Motorcycle life. I run my old KTM420 MC80's on 100LL & 32:1 synthetics of various brands as it runs smoother and cooler with the 100LL have since 1980. (Especially in low speed situations like woods riding in low gears..not a lot of cooling going on with low speed riding) I haven't seen a reason to go back to separate mixes yet... Performance at the GTG's and in the woods might. Just haven't so far. Maybe we will test the "optimal" mix with timed runs in out "Poulan" race we will hold at the next GTG along with testing 3/8 vs the smaller low pro chains. One thing I can say for certain, when I was milling, the saws ran cooler with the 100LL with no loss in time. So I ran it exclusively when I milled.
This brings up the main issue for me when tuning my stuff...duration of work cycle. During a day in the woods, it might start at 50 degrees and end at 85 here in CNY so you would think theoretically you should lean out the saw as the day goes on, right? Also the "work cycle" might be 15-20 seconds per cut in one situation..then 2-3minutes when ripping fence post in another. I want to tune my stuff at the point of where the temperature is at the high side of the typical work cycle so I'm tuning to the worst condition on initial tweaking. AND different mixtures can effect where that steady state high point is. After fiddling with this for years..I ultimately just do plug checks on the first couple of jobs when I setup & learn my saws and look to tune for the lowest common denominator and this ends up being tuned a bit rich. My stuff runs. Once in a while I have to tune a bit to more extreem situations...like when I was cutting in 0 degee winter days...or last week in humid 88 degree days. I just report what I see real time.
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o8f150
Tree Freak
i always use the 93 octane with a bit of marine stabile which helps with the ethonal
You DON't , ALWAYS have to lean out with 100 LL. My 028S, 038M, Br400 blower and Husky weed wacker run great with same settings as crap gas.
My other saws all have needed 1/8-1/4 leaner on high, most were fine on low, or -1/8.
The one that likes the 100LL the best is the 028S, it got a new P/C years ago and was tuned to run pre-corn fed. That saw will start, 3 pulls after sitting 4-6 months with the same 100LL in the tank, 1 pull when hot. If it has been summer, I'll put the gas in my tractor if more than 6-months old.
My other saws all have needed 1/8-1/4 leaner on high, most were fine on low, or -1/8.
The one that likes the 100LL the best is the 028S, it got a new P/C years ago and was tuned to run pre-corn fed. That saw will start, 3 pulls after sitting 4-6 months with the same 100LL in the tank, 1 pull when hot. If it has been summer, I'll put the gas in my tractor if more than 6-months old.
spacemule
The Peanut Gallery
Here's your sign.
I've used 100ll for years in all my 2-cycle stuff, my mower (lawnboy), trimmer and my saws with no problems. My excuse is: I work @ the airport and I get it for free. Nuff 'said.
Use a good oil with it (not gonna get into it) and you're good to go. Of course perform, or learn to perform the adjustments required for day to day use. In the mountains here, we even have to re-tune a bit when we cut @ home, as the altitude from site to site makes a difference! Also, not advised to use leaded gas in a saw with a catalytic converter as it will wreck it chemically and plug it physically. Some fouling of the plug may be experienced as well, but I haven't noticed enough build up to warrant cleaning before I would normally change the plug anyways.
Good Luck!
Old51AVE :greenchainsaw:
Use a good oil with it (not gonna get into it) and you're good to go. Of course perform, or learn to perform the adjustments required for day to day use. In the mountains here, we even have to re-tune a bit when we cut @ home, as the altitude from site to site makes a difference! Also, not advised to use leaded gas in a saw with a catalytic converter as it will wreck it chemically and plug it physically. Some fouling of the plug may be experienced as well, but I haven't noticed enough build up to warrant cleaning before I would normally change the plug anyways.
Good Luck!
Old51AVE :greenchainsaw:
JJay03
ArboristSite Guru
Prob best not to run avgas if the saw is not tuned and timed for it correctly. That is why it would run rich also on avgas cause you are having gas that is not being burned all the way cause the spark is not advanced enough. If you leaned the saw out for it then you would just lose performance over pump gas since the avgas would burn slower it needs more time to burn. Use what the manual calls for the saw is designed to run that octane.
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100LL is a slower and cooler burning fuel. It is not an ideal fuel for use in OPE. It does help deal with some of the storage problem, but that's it's only advantage. Many saws do not idle well with it, throttle response is down, and if anything, will cut a hair slower.
But if tuned correctly to 100ll does it leave less buildup on the piston and ports? Anyone have a comparison? If storage is the only benefit then I micht just switch back to pump.
I can't answer that from direct experience, but if anything, I would expect it to have more buildup. It burns slower, and therefore will not burn as completely. Tuning and oil likely have more to do with it though.
I ran high test for a little while and it's simply not worth the hassle. Run good oil and keep the saw tuned properly and carbon shouldn't be an issue. 
It surely would be much easier to run pump, I just recently did a little night ops to the local spot and it was a bit stressful. Might have to switch back.
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