40:1, 50:1 does it matter?

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bikemike said:
Yes it does. Find a old thread and you get called names. Lmao
Click to expand...
New members do read OLD threads. The information is NEW to us.

The question I have that so far I've NEVER seen discussed is something mathematical that I've talked to lots of smart people about and either I'm a dummy or an over thinker.
I'd like to post a question based upon the belief that as others join and read these old posts, someone may be able to help me with my math.
Here it is: One US gallon is 128 ounces. Therefore seeking a 40:1 ratio by dividing 128 by 40 we get 3.2 for an answer. On this we all agree. BUT, when we add 128 + 3.2 out net volume increases to 131.2.
How can we have a true 40:1 ratio based upon a net volume of 131.2 when the added oil is 3.2, ?
If 131.2 is divided by 3.2 we get 41 for the answer.
While this is small it's incorrect in my mind.
Am I doing the math wrong?
When I mix I mix the entire net volume with oil included to equal 128 ounces. I mix 2 gallons at a time. I level my container to be sure the fuel correctly touches the 128 ounce mark precisely.
In my experience my saws seem more predictable and need less tuning when my petrol mix is more precise.
After reading this OLD post tonight, which I very much appreciate, one post stood out. The idea of using a bottle of 6.4 ounces of oil to 2 gallons of gasoline for a 40:1 ratio seems smart especially since I'm already mixing 2 gallon at a time.
I can do that easy.
Now my original question?
Probably don't make a big difference but if we split hairs, we do need to keep the net content 128 ounces, correct?
 
Canyonbc said:
Well here is the way i see it...especially with that nice of a saw.

There has to be a reason that Stihl would say use 50:1.

The other is think...what 40:1 and 50: 1 is.

40:1 - 40 parts gas to 1 part oil

50:1 - 50 parts gas to 1 part oil

50:1 is gonna run hotter and faster. The 200T, has been designed to run at 50:1, and that is what we should run at. It would seem to me that you would be bogging down your machine and running to much oil through it.

Again, JMO...

Finally...if Stihl wanted 40:1 ran through it they would stamp use 40:1 mix.

Canyon
Click to expand...
The only reason Stihl & others state 50/1 mix it to comply with the US emissions with out a saw redesign If you read the literature on obtaining power from a 2 smoke motor you will find as the tuning guru's did/do the more oil in the mix (within reason) the harder /better it will run with correct tuningNot Bull s**t proven by running/performance the logic if you consider it Metal parts running lubed by minute amounts of oil & mostly lubed with almost neat gas & then there's the straight gassing doesn't run for long But each to his own you are paying the repair bills
 
Wow said:
New members do read OLD threads. The information is NEW to us.

The question I have that so far I've NEVER seen discussed is something mathematical that I've talked to lots of smart people about and either I'm a dummy or an over thinker.
I'd like to post a question based upon the belief that as others join and read these old posts, someone may be able to help me with my math.
Here it is: One US gallon is 128 ounces. Therefore seeking a 40:1 ratio by dividing 128 by 40 we get 3.2 for an answer. On this we all agree. BUT, when we add 128 + 3.2 out net volume increases to 131.2.
How can we have a true 40:1 ratio based upon a net volume of 131.2 when the added oil is 3.2, ?
If 131.2 is divided by 3.2 we get 41 for the answer.
While this is small it's incorrect in my mind.
Am I doing the math wrong?
When I mix I mix the entire net volume with oil included to equal 128 ounces. I mix 2 gallons at a time. I level my container to be sure the fuel correctly touches the 128 ounce mark precisely.
In my experience my saws seem more predictable and need less tuning when my petrol mix is more precise.
After reading this OLD post tonight, which I very much appreciate, one post stood out. The idea of using a bottle of 6.4 ounces of oil to 2 gallons of gasoline for a 40:1 ratio seems smart especially since I'm already mixing 2 gallon at a time.
I can do that easy.
Now my original question?
Probably don't make a big difference but if we split hairs, we do need to keep the net content 128 ounces, correct?
Click to expand...
If you have a litre measure & add 25 ML 's of oil to each Litre it give 's an accurate 40/1 ratio mix
 
Wow said:
New members do read OLD threads. The information is NEW to us.

The question I have that so far I've NEVER seen discussed is something mathematical that I've talked to lots of smart people about and either I'm a dummy or an over thinker.
I'd like to post a question based upon the belief that as others join and read these old posts, someone may be able to help me with my math.
Here it is: One US gallon is 128 ounces. Therefore seeking a 40:1 ratio by dividing 128 by 40 we get 3.2 for an answer. On this we all agree. BUT, when we add 128 + 3.2 out net volume increases to 131.2.
How can we have a true 40:1 ratio based upon a net volume of 131.2 when the added oil is 3.2, ?
If 131.2 is divided by 3.2 we get 41 for the answer.
While this is small it's incorrect in my mind.
Am I doing the math wrong?
When I mix I mix the entire net volume with oil included to equal 128 ounces. I mix 2 gallons at a time. I level my container to be sure the fuel correctly touches the 128 ounce mark precisely.
In my experience my saws seem more predictable and need less tuning when my petrol mix is more precise.
After reading this OLD post tonight, which I very much appreciate, one post stood out. The idea of using a bottle of 6.4 ounces of oil to 2 gallons of gasoline for a 40:1 ratio seems smart especially since I'm already mixing 2 gallon at a time.
I can do that easy.
Now my original question?
Probably don't make a big difference but if we split hairs, we do need to keep the net content 128 ounces, correct?
Click to expand...
Nope, as long as you mixed the 128 oz of fuel with 3.2 oz of oil you get 131.2 oz of a mixture at the ratio of 40:1.

If you are adding fuel to 3.2 oz of oil for a final volume of 128 oz then your ratio is (128 - 3.2)/3.2 = 39, so 39:1
 
Wow said:
Now my original question?
Probably don't make a big difference but if we split hairs, we do need to keep the net content 128 ounces, correct?
Click to expand...
I deo not see a need to have the final volume matter. If you want to go down that road(splitting hairs) one needs to know if the end volume is really the sum of the two, often the final volume is less than the sum for liquids, like alcohol and water. A pail of sand and a pail of stone does not end up as two pails of mix.

A pound cake is a pound of various ingredients not the cake is a pound after it comes out of the oven.
 
I have more run time with 2 smoke motors than most. Here is what I have found with many hours on many motors. 50:1 is a little lean for certain conditions, but that does not mean that a motor will seize after five minutes of operation. My personal preference is 34:1 with good oil. It is very rare that a modern engine wears out from an enormous amount of hours run. Seals wearing out from being dry get more engines down than other issues. So the mix that one chooses to run does not matter much. Whatever the mix used is it needs to be consistent along with carburetor adjustment for changing conditions. Most people use a honest mix ratio. They put a certain amount of gasoline into a container and then add oil. So as an example when I mixed 5 gallons I put close to five gallons in a container and then added a measured 18 ounces into the can thus overfilling the container slightly. There are many many other methods. And they do not matter. Come up with a consistent plan and go cutting. If you end up with 38.54:1 or 40.98:1 it does not matter as long as it is close to the same each time then you are good to go. Choose a ratio that seems the best for you and make the chips fly. Thanks
 
Duce said:
It really only matters, if you want to argue! :drinkingcoffee:
Click to expand...
I never want to argue but I'm a very curious mind. When I was in Electronics School we took our equations to Nano, 9 zeros or Pico, 12 zeros.
However, after reading this post my conclusion is that I still don't trust 50:1 do trust 40:1 but can accept a small variation of a point either way.
I will continue to strive for consistency. I'm running 1 old Poulan and
3 old Sthils that call for 40:1 and 3 relatively new Echo's that call for 50:1, I'm going to be happy with 39:1 or 41:1 or as near to 40:1 as I can manage.
The OTHER question in my mind is how more oil effects the performance of the engine.

Once I (old and forgetful) mixed fuel and forgot I'd already added oil. I accidentally doubled the oil. Realized my mistake and tested the mix in a cheap string trimmer. The motor would not wind up. The trimmer ran thought but seemed to be running rich. Oil actually came out the exhaust.
Put fresh 40:1 ?ish in and it runs great.

Consistency in mix may be more important.
Thanks for the help
 
Has anyone ran the M-Tronic Stihls on 40:1 ? I'm all for extending my saws life. I've just always used whatever the manual said to use, which in this case is 50:1.
 
Overkill338 said:
Has anyone ran the M-Tronic Stihls on 40:1 ? I'm all for extending my saws life. I've just always used whatever the manual said to use, which in this case is 50:1.
Click to expand...
I've bought 4 new Echo saws In the last 3 years. When I buy I have the dealer set my saws for 40:1 and a tad rich. After a saw is broken in I've tuned the carb within the limiters. So far so good.
 
The best mix is 50/50 30wt bar n chain oil n 87 e10 cheap gas....Works best in summer like temps iffin you were your hat backwards n chew Copenhagen stuffs!!!!!!Also remove all paint from your blade in order to reduce heat!:chainsaw::givebeer:
 
Overkill338 said:
Has anyone ran the M-Tronic Stihls on 40:1 ? I'm all for extending my saws life. I've just always used whatever the manual said to use, which in this case is 50:1.
Click to expand...

Plenty of people have, there's a guy who ran some tests as well. If it's a stock saw, 40:1 is just fine, if they're ported, those guys like to run a few drops more oil.
 
Wow said:
New members do read OLD threads. The information is NEW to us.

The question I have that so far I've NEVER seen discussed is something mathematical that I've talked to lots of smart people about and either I'm a dummy or an over thinker.
I'd like to post a question based upon the belief that as others join and read these old posts, someone may be able to help me with my math.
Here it is: One US gallon is 128 ounces. Therefore seeking a 40:1 ratio by dividing 128 by 40 we get 3.2 for an answer. On this we all agree. BUT, when we add 128 + 3.2 out net volume increases to 131.2.
How can we have a true 40:1 ratio based upon a net volume of 131.2 when the added oil is 3.2, ?
If 131.2 is divided by 3.2 we get 41 for the answer.
While this is small it's incorrect in my mind.
Am I doing the math wrong?
When I mix I mix the entire net volume with oil included to equal 128 ounces. I mix 2 gallons at a time. I level my container to be sure the fuel correctly touches the 128 ounce mark precisely.
In my experience my saws seem more predictable and need less tuning when my petrol mix is more precise.
After reading this OLD post tonight, which I very much appreciate, one post stood out. The idea of using a bottle of 6.4 ounces of oil to 2 gallons of gasoline for a 40:1 ratio seems smart especially since I'm already mixing 2 gallon at a time.
I can do that easy.
Now my original question?
Probably don't make a big difference but if we split hairs, we do need to keep the net content 128 ounces, correct?
Click to expand...
The gas doesn’t dissolve the oil.
It mixes with it.
One gallon plus so many ounces of oil equals......well......one gallon and however many ounces you added.
You don’t end up with a gallon....... oh yeah.....it doesn’t matter
 

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