40:1, 50:1 does it matter?
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opcorn: :sword: Ole Farmerbuck
Addicted to ArboristSite
The owners manual that came with my super xl says to use a good quality SAE-30 motor oil. Preferably Homelite Motor Oil. I think i'll use 2 stroke though.
ShockaSPY
New Member
100:1?
I let someone borrow one of my 310's and when I got it back it had crap compression. Took a sample of the gas to ABC(Local Performance Shop) and the mixture was 85:1. 100:1 sounds like nothing but problems. I should have let that person borrow a junk echo... if I had an echo....
I let someone borrow one of my 310's and when I got it back it had crap compression. Took a sample of the gas to ABC(Local Performance Shop) and the mixture was 85:1. 100:1 sounds like nothing but problems. I should have let that person borrow a junk echo... if I had an echo....
cjk
ArboristSite Operative
From what I understand, the 100:1 Amsoil is a special synthetic oil designed for 100:1 mix. I wouldnt try mixing just any oil at 100:1.
If I was after the most power out of an engine(racing), I may try it. It should, theoretically allow more gas to get burned and produce more energy. Gas has more energy than oil. So more gas and less oil should give more power. But there must be a fine line there somewhere......
I do not use 100:1. I figure the extra cost of the "special" oil evens out any $$ savings and Im not racing anyone.
I would love to see a test with 2 identical saws, 1 running the 100:1 and one the factory recommended mix. Maybe even another saw running extra oil. Tear them down after an equal amount of hours/work and see what they look like. It would be tough to control all the conditions in the experiment.
Any volunteers? I think this is why we dont see a lot of DATA on this type of issue.
If I was after the most power out of an engine(racing), I may try it. It should, theoretically allow more gas to get burned and produce more energy. Gas has more energy than oil. So more gas and less oil should give more power. But there must be a fine line there somewhere......
I do not use 100:1. I figure the extra cost of the "special" oil evens out any $$ savings and Im not racing anyone.
I would love to see a test with 2 identical saws, 1 running the 100:1 and one the factory recommended mix. Maybe even another saw running extra oil. Tear them down after an equal amount of hours/work and see what they look like. It would be tough to control all the conditions in the experiment.
Any volunteers? I think this is why we dont see a lot of DATA on this type of issue.
Saw Bones
ArboristSite Operative
this topic has been beat to death. Do a Search and you will find hours and hours of reading on it.:deadhorse:
We had a training session last week with the Stihl tech manager. I will try and tell some of the things we were told, but unfortunately, my old brain can't remember some of the technical reasonings. Some of you may not agree with the reasons, but I'm only the messenger here.
Also most of this relates to the new saws that are designed to meet the emission standards of California Air Quality Board and the European Union which also has strict air emission standards. To meet their requirements, the operating heat range has a tight range.
Octane ratings - use only 89 or higher. Apparently, the octane changes the burn rate within the combustion chamber and the higher octane gives a more even controlled burn. Therefore, the lower octane fuel causes the saw to run too hot.
The new saws have redesigned carbs that self adjust their richness, so we were told that the high/low speed jets should never be adjusted in the field. And no adjustment should be done without using a tach as a change in 1000 rpms from optimum can cause problems.
If you run the gas/oil mix too rich, you are just as liable to burn up the saw as if you were to run it too lean. I believe the explanation for this is because the fuel in the crankcase being vapourized provides most of the engine cooling. A richer mix vapourizes at a hotter temperature, causing the engine to run hotter.
The new double barreled carbs now have check valves in them that will be damaged if you blow out the carb with compressed air.
The old cylinders were ported in such as way that as much as 25% the gas was wasted going through the exhaust port. The new cylinder ports are designed to only lose 3 %.
The 2 cycle oil used has to be blended for use in an AIR cooled engine. Because water cooled 2 cycles (ie outboard motors) run cooler, the operating characteristics of the oil is different. It was recommended to use high quality 2 cycle oil designed for air cooled engines. We don't use Stihl oil, but the oil we used passed muster.
People have a right to be skeptical given the source of information, but he was very good at showing (using demo saws with portions removed) the differences between the new model and older model saws. If anyone has a chance to talk to one of the factory tech service reps (the guys who train the dealer service techs) its worth the time.
BTW, I don't work for Stihl. I'm sure the Husky rep would have been just as informative.
Also most of this relates to the new saws that are designed to meet the emission standards of California Air Quality Board and the European Union which also has strict air emission standards. To meet their requirements, the operating heat range has a tight range.
Octane ratings - use only 89 or higher. Apparently, the octane changes the burn rate within the combustion chamber and the higher octane gives a more even controlled burn. Therefore, the lower octane fuel causes the saw to run too hot.
The new saws have redesigned carbs that self adjust their richness, so we were told that the high/low speed jets should never be adjusted in the field. And no adjustment should be done without using a tach as a change in 1000 rpms from optimum can cause problems.
If you run the gas/oil mix too rich, you are just as liable to burn up the saw as if you were to run it too lean. I believe the explanation for this is because the fuel in the crankcase being vapourized provides most of the engine cooling. A richer mix vapourizes at a hotter temperature, causing the engine to run hotter.
The new double barreled carbs now have check valves in them that will be damaged if you blow out the carb with compressed air.
The old cylinders were ported in such as way that as much as 25% the gas was wasted going through the exhaust port. The new cylinder ports are designed to only lose 3 %.
The 2 cycle oil used has to be blended for use in an AIR cooled engine. Because water cooled 2 cycles (ie outboard motors) run cooler, the operating characteristics of the oil is different. It was recommended to use high quality 2 cycle oil designed for air cooled engines. We don't use Stihl oil, but the oil we used passed muster.
People have a right to be skeptical given the source of information, but he was very good at showing (using demo saws with portions removed) the differences between the new model and older model saws. If anyone has a chance to talk to one of the factory tech service reps (the guys who train the dealer service techs) its worth the time.
BTW, I don't work for Stihl. I'm sure the Husky rep would have been just as informative.
Nate Surveyor
ArboristSite Lurker
Just a comment
IF you run richer mix, then the mixed fuel is THICKER, and runs SLOWER through the saw, and thus it runs LEANER, on the air fuel ratio.
If you can run around 35:1, AND rejet it, to run rich enough, then the thing will dribble oil out the exhaust, and power will be good, and it will last a long time.
Running too much oil can foul a plug.
So, we have a 3 way ratio.
GAS/OIL/AIR.
don't forget about the air!
Nate:greenchainsaw:
IF you run richer mix, then the mixed fuel is THICKER, and runs SLOWER through the saw, and thus it runs LEANER, on the air fuel ratio.
If you can run around 35:1, AND rejet it, to run rich enough, then the thing will dribble oil out the exhaust, and power will be good, and it will last a long time.
Running too much oil can foul a plug.
So, we have a 3 way ratio.
GAS/OIL/AIR.
don't forget about the air!
Nate:greenchainsaw:
retired redneck
ArboristSite Guru
Mobil 1 r 2t at 32/1 adjust carb to run on this mix,i have used this mix for ever ,never a bad piston or jug no carbon probs.............
Dennis_Peacock
ArboristSite Operative
I've ran Amsoil 100:1 two cycle oil in all my saws, weedeaters, blowers, and trimmers since 1986. Never had any problem with any of them. My last weedeater lasted me 20 years and I would still have it today if I could have found some replacement parts for the thang that just plain wore out. I've used it for over 20 years and I'll keep using it. Works great and I get better power than using the Stihl premium 2SO.
huskykid141
ArboristSite Operative
Running a richer fuel mix it best because it the oil is used to lubricate the piston and cylinder because the two stroke dosen't have motor oil in the crankcase like a four stroke. Also running a richer fuel mixture will never burn out a saw. The saw will bog down and it will fowl plugs but your better off running a two stroke or any engine richer. If you run it too lean you will burn out the engine and then your talking big bucks. The most that will happen running a engine too rich is you fowl a plug or have some carbon build up. I was always told your better running rich than too lean.
retired redneck
ArboristSite Guru
ApexTreeService
ArboristSite Operative
Well I've been running Amsoil Saber 100:1 for about a year now with no problems. I like it because you only have to buy $ half as much, so it saves me $ there. I really like how little the saws smoke. Used to smoke ya out when cutting off a stump burning 50:1. With 100:1 there isn't that haze near the ground where your kneeling. The Amsoil has a blue die in it. I also ran it in my two stroke dirt bikes all summer. I trust Amsoil products, I think it is a quality product.
Now here's something that hasn't been said here, or as far as I know anywhere else either. I don't think that I've ever completely emptied my gas jugs. They might get down to the point where there is one tank full and then I fill them. In topping the tank off and then adding a full container of oil I always have a richer ratio because there is already some mix (50+:1) plus a complete bottle of oil. Does that make sense? Did I blow anyone's mind?
scotclayshooter
Addicted to ArboristSite
Timberwolf says ure 40:1 so thats good enough for me!
huskystihl
Addicted to ArboristSite
I agree! I run it now over stihl because of price. I run it at around 75:1 though. No problems in day to use.
hwrdpromac7900
ArboristSite Operative
Anyone ever try running rc fuel in a chain saw? I mean come on, 30% nitro it's gotta run for at least 3 seconds.:chainsawguy:
crmyers
ArboristSite Operative
I tried it in a weed whacker once. That thing would scream but the alcohol eat up the fuel lines and the carb diaphragm. The exhaust was murder to.
hwrdpromac7900
ArboristSite Operative
Sweet!
Terry Syd
Addicted to ArboristSite
Synthetics vs petroleum
I wrote an article on motorcycle oils a couple of decades ago. There were two different wear tests that the oils were subjected to. The oil that came out the least amount of wear was castor oil, followed by various synthetics and carrying up the rear was petroleum based.
The synthetics have improved since then and you don't have to worry about gumming up the rings like with castor oil.
As for keeping a two-stroke engine running; I remember a desert race where the leader ran out of fuel four miles from the finish. He pushed over to a motorhome and got some fuel, splashed in some ATF and ran the guts out of the engine to the finish and won the race.
I remember another fellow that seized his engine at an enduro because he forgot to add his oil to the fuel. Stuck beside the trail, he emptied a small spray can of chain oil into his tank, sloshed it around, and then went on to finish the enduro.
A two-stroke can take all sorts of oil to keep it running, however long term wear is another matter.
Take a look at your rings. If you see small brown or blue spots on the surface of the rings then the oil film is breaking down and you are getting metal to metal contact.
Now here's a point that nobody addresses - air filtration. The layer of oil on the surfaces in side the cylinder are extremely small, however dust is many more times larger than that layer. That is what gives your piston the nice clean looking piston skirt - dust. If your piston skirt has a layer of baked on carbon, then you are running clean air.
Most, if not all, two-stroke oils that are on the market can do the job. However, if you can't be bothered to keep the dust out of the engine, you might as well run the cheapest oil available.
I wrote an article on motorcycle oils a couple of decades ago. There were two different wear tests that the oils were subjected to. The oil that came out the least amount of wear was castor oil, followed by various synthetics and carrying up the rear was petroleum based.
The synthetics have improved since then and you don't have to worry about gumming up the rings like with castor oil.
As for keeping a two-stroke engine running; I remember a desert race where the leader ran out of fuel four miles from the finish. He pushed over to a motorhome and got some fuel, splashed in some ATF and ran the guts out of the engine to the finish and won the race.
I remember another fellow that seized his engine at an enduro because he forgot to add his oil to the fuel. Stuck beside the trail, he emptied a small spray can of chain oil into his tank, sloshed it around, and then went on to finish the enduro.
A two-stroke can take all sorts of oil to keep it running, however long term wear is another matter.
Take a look at your rings. If you see small brown or blue spots on the surface of the rings then the oil film is breaking down and you are getting metal to metal contact.
Now here's a point that nobody addresses - air filtration. The layer of oil on the surfaces in side the cylinder are extremely small, however dust is many more times larger than that layer. That is what gives your piston the nice clean looking piston skirt - dust. If your piston skirt has a layer of baked on carbon, then you are running clean air.
Most, if not all, two-stroke oils that are on the market can do the job. However, if you can't be bothered to keep the dust out of the engine, you might as well run the cheapest oil available.
