Fuel Ratio

[gr8mac]

This may be a dumb question but..... Where can I find a good ratio mix chart?
I usually mix up a gallon (50 to 1) at a time and alot of the charts I see don't show for this. I have many saws that require different ratios and I want to make sure I get it right. Thanks.

 

[fishhuntcutwood]

Couldn't you use a calculator? Pretty simple math actually. Stihl sells mix in a bottle that allows for different ratios to be measured out.

Jeff

 

[TimberPig]

Or go to a motorcycle shop and get a ratio rite cup.

 

[gr8mac]

Re:

I'm not that smart fish. Why should I go get something at a motorcycle shop when I can use my wife's measuring cup..... Until she finds out that is.

 

[fishhuntcutwood]

Here's a sample-
Using a 50:1 bottle of mix.

50:1= 1 gal.
40:1=.8 gal.
32:1=.64 gal.

Find the ratio, relative to 50:1. 40:50 is .8. 32:50 is .64

Jeff

 

[Lakeside53]

Here's a sample-
Using a 50:1 bottle of mix.

50:1= 1 gal.
40:1=.8 gal.
32:1=.64 gal.

Find the ratio, relative to 50:1. 40:50 is .8. 32:50 is .64

Jeff

Now I'm confused

 

[fishhuntcutwood]

Now I'm confused

If I've got a bottle of Stihl mix, which is supposed to be 50:1, and meant to be used with one gallon of gas, and I want to use it as 40:1, I have to use less gas because I have a premeasured amount of oil. To step the amount of gas down proportionately, I have to find the ratio of 40:50 which is .8:1. Where I needed one gallon to mix 50:1, I now need .8 of a gallon to mix the same bottle of Stihl oil to 40:1.

Seventh grade math class....

Jeff

 

[Lakeside53]

If I've got a bottle of Stihl mix, which is supposed to be 50:1, and meant to be used with one gallon of gas, and I want to use it as 40:1, I have to use less gas because I have a premeasured amount of oil. To step the amount of gas down proportionately, I have to find the ratio of 40:50 which is .8:1. Where I needed one gallon to mix 50:1, I now need .8 of a gallon to mix the same bottle of Stihl oil to 40:1.

Seventh grade math class....

Jeff

But where am I going to get a .8 gallon container??

 

[ray benson]

Many charts out there.
http://www.chainsawsforsawmills.com/mixingchart.htm

 

[tony marks]

go to the gas pump and pump .8 gal into the container after u have put in the 1 gal mix of oil.

 

[davefr]

The saws really don't care about the ratio as long as the right oil is used at that ratio. (ie ratio is more a function of oil technology then engine technology.)


I use Mobil MX2T or R2T and mix it about 40:1 and use it in everything. I even used it in my old John Deere that specified 16:1.

50:1 = 2.6 oz oil/gal
40:1 = 3.2 oz oil/gal
32:1 = 4.0 oz oil/gal

The above are the most common ratios. There's an endless debate about which ratio is best. Manufacturers say 50:1 but EPA is influencing their recommendation. Some say 32:1 for heavy cutting conditions.

 

[PWB]

That's why the metric system is SO nice! The small bottle is 100ml (1/10 of a litre)
Put it in 5 litres, 50 to 1
4 litres, 40 to 1
etc, etc, etc............
Maybe you americans should step into the 20th century. We'll worry about getting you caught up to the rest of the world when you make it that far. j/k

 

[gr8mac]

Thanks for all the comments guys, and for the chart Ray.

 

[smokechase II]

40:1

Davefr:
"ratio is more a function of oil technology then engine technology."
"Manufacturers say 50:1 but EPA is influencing their recommendation."

To back you up. In Alaska, the fire fighting organization there had to give up on supplying all the different mix ratios for this pump, that brand of saw etc.
Logistically, re-supply by helicopter and the remixing of fuel in the field from one ratio to another was just too hard.
So they went with just one ratio, provided it started with a high quality mix oil.

Mark III pumps, which have been a standard in fire fighting operations for decades, had their manufacturer change their ratio from 16:1 to 24:1. Again, the engine didn't change, but the mix oils are certainly better.

At Stihl NW recently, I asked specifically about fire fighters going to a stronger mix for hotter conditions on the fireline. Re-assured that Stihl 50:1 is just fine. Not necessary.

If I decided to copy you and just go with 40:1 mix, provided I use Stihl or Husky mix, what, if any, problems might I encounter?
Spark plug fouling, muffler screen, less power, or maybe just a little more smoke at warm up?
Thanks

 

[oakman]

i don't like to buy .8 of a gallon of fuel, and i don't like those little pre-measured bottles of oil, so i do it this way.
1 gallon = 128 fl. oz.
divide 128 by whatever ratio you want, 50, 40, 32, or 37. whatever.
the result will be the amount of oil to add in fl. oz.
example- 128 divided by 32 = 4
128 divided by 40 = 3.2
128 divided by 50 = 2.56

 

[John Ellison]

I think Timberpigs suggestion of motorcycle shop/ ratio rite cup is a good one. I bought one a couple of years ago and it is perfect. Easy to clean and you can easily mix any amount of gas at any ratio just by looking at the marks on the cup.

 

[bump_r]

I, myself do not burn enough fuel mix to justify buying "bulk" mix oil. Them little Stihl bottles are just too convenient for me. I keep a bottle in each saw case so I can always mix more "in the field" should the need arise. Removes the temptation to mix more than I could use before it went stale. Also, I can see a need for a chart to indicate how much gasoline to add to a predetermined volume of mix oil to achieve a non-standard (other than factory recommended) ratio. For example, I can easily take my 2.5 fl. oz. bottle of oil, mix it to the recommended 1 gallon of gasoline to get the recommended 50:1 - but I want to make it 40:1 for this tank for some reason. Yeah, retune the carb, yadda yadda... So, back at the pump, I have not calculator, I don't want to risk a piston and jug to math in my head. Ha-HA! I whip out the handy chart! Someone check my math before someone junks their saw, though! It's just easier for some to use pre-measured oil containers and let the gas pump measure the gas...

 

[Tree Sling'r]

I mix mine 5 gallons at a time. So for me, 50:1 is 5 gallons, 45:1 is 4.5 gallons, 40:1 is 4 gallons. Usually run about 48:1.

 

[WRW]

That's why the metric system is SO nice! The small bottle is 100ml (1/10 of a litre)
Put it in 5 litres, 50 to 1
4 litres, 40 to 1
etc, etc, etc............
Maybe you americans should step into the 20th century. We'll worry about getting you caught up to the rest of the world when you make it that far. j/k

If the metric system is so great, why doesn't a clock have ten numbers instead of twelve?

 

[IndyIan]

http://zapatopi.net/metrictime/