2 cycle oil mix ratio help

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I have a two cycle trimmer. I had some Super TECH Universal 2-cycle oil (blue bottle). The trimmer was a 40:1 ratio. I filled my gas can with 1 gallon. I am not sure what the mix ratio is...I can't figure it out. Isn't that awful.
 
You divide the number of ounces of gasoline by the mix ratio that you wish to achieve and it will give you the amount of oil in ounces of two-cycle oil to use.

Example:

for one gallon (128 ounces)

128 ÷ 40 (desired mix ratio) = 3.2 ounces of oil

(ounces of gas) ÷ (desired mix ratio) = (amount of oil to use)
 
Thanks for that. Funny (or not), I google that and came up with the Website that does that calculations. Hard to fathom all the info on the net. I usually do a google search on most stuff but enjoy the "comfort" of Bob's.
 
It's good (best) to know how even if it is available on the net.
 
Using 1 gallon as the total volume (128 ounces), divide that by your known amount of 40 parts of gas and you'll get the amount of oil needed. You can check it by multiplying the answer by the ratio (40)

Or, you can just start simple and work up to it:

2:1 (128:64) ounces gas/ounces oil
4:1 (128:32)
8:1 (128:16)
16:1 (128:8)
32:1 (128:4)

Using this method, (for the math impaired), you know that you'll at least need LESS than 4 ounces of oil. But really, just do it like I showed you above...

edit: Ooops, looks like I'm late to the party....
 
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When I had an RM-125, I spent a lot of time mixing racing gas and oil. I am a physics major, pretty good at math...

But for the bike, I bought a specially-made jug that had a main compartment for gas that was graduated in liters and another compartment for oil that was graduated with multiple scales based on desired mix ratio.

So, you would fill the gas portion of the jug to...say "6". Then you look at the oil portion, pick your scale...say, "40:1"...and fill the oil up to the "6" on that scale. Invert the jug and mix 'em up.

It was great for mixing different ratios, in small quantities...and the best part? No math errors!

But, now you know why all the major OPE manufacturers sell little 3.2 OZ bottles of oil...
 
Originally Posted By: coopns
I had some Super TECH Universal 2-cycle oil (blue bottle). The trimmer was a 40:1 ratio.

Just to be clear, the ratio is determined by the particular 2-cycle oil that you're using and not by the trimmer itself. So, you should refer to the instructions on the bottle.
 
When you encounter a math problem with ratios and you only have two numbers to calculate, you typ divide or multiply. Obviously its not 128 * 40 so, it's either = 12.8/4 or 4/12.8. You might assume the mix would be require at least 1 oz of oil, so v = 12.8 / 4 would be the best guess. You do have to know how many oz per gallon, but recalling 2 pints per 1-Qt, then, 4-Qts per 1-Gallon will get you there.

Now if you had 3/4th a gallon of gas previously mixed at 100:1 and you wanted to add TCW3 to get you to 40:1 - that solution requires heavier lifting
wink.gif
 
Originally Posted By: Quattro Pete
Originally Posted By: coopns
I had some Super TECH Universal 2-cycle oil (blue bottle). The trimmer was a 40:1 ratio.

Just to be clear, the ratio is determined by the particular 2-cycle oil that you're using and not by the trimmer itself. So, you should refer to the instructions on the bottle.




With all due respect, I disagree. The guy who builds the particular equipment should be the guy you listen to regarding mix ratios. In others words, if Stihl says to mix their trimmers at 50:1, then you should follow that advice in lieu of what is printed on the side of an oil bottle.

Having said that, I do have Stihl OPE that recommends 50:1 ratios. Yet, I use Amsoil Sabre 100:1 in all of them. But as per my comment above, I always mix the Sabre at the Stihl recommended ratio of 50:1.

If Amsoil figures their Sabre is good enough to run at 100:1, then I know it will definitely be good enough (better) at the Stihl recommended ratio of 50:1.

I know there are lots of folks who ignore OPE manufacturer's recommended ratios, but I really don't know why. I'd save very little money running my OPE at 100:1, for instance, and the brain damage it would give me would not be worth it.
 
Originally Posted By: propuckstopper

With all due respect, I disagree.
You have the right to do so. This subject was discussed at length here in the past if you do a search.

Quote:
The guy who builds the particular equipment should be the guy you listen to regarding mix ratios. In others words, if Stihl says to mix their trimmers at 50:1, then you should follow that advice in lieu of what is printed on the side of an oil bottle.

You may want to pay more attention to the wording in your Stihl owner's manual. I've got two pieces of Stihl equipment, and both of them just say that if you're using Stihl 2-cycle oil (which they obviously recommend), then you should mix it at 50:1 ratio. They don't say what ratio should be used if you're using someone else's oil.

Another example is fuel additives/system cleaners for your car. Have you noticed that different ones should be added into your tank in different proportions? Wonder why?

Quote:

If Amsoil figures their Sabre is good enough to run at 100:1, then I know it will definitely be good enough (better) at the Stihl recommended ratio of 50:1.

My guess is that Sabre is more concentrated, so you need to use less of it. Why do you assume that more oil is better? By the same logic, if 50:1 is better than 100:1, then surely 5:1 should be even better than 50:1, right?

Too much oil can foul your plugs and possibly cause other issues.
 
Originally Posted By: Quattro Pete
Originally Posted By: coopns
I had some Super TECH Universal 2-cycle oil (blue bottle). The trimmer was a 40:1 ratio.

Just to be clear, the ratio is determined by the particular 2-cycle oil that you're using and not by the trimmer itself. So, you should refer to the instructions on the bottle.




NO NO NO! Mix at what the equipment requires, and recommends.
 
I can't believe how often this discussion comes up and the varied, unsupported opinions that participants offer.

Mix the fuel at the manufacturers recommended ratio. Plain and simple. If you're going to flog the equipment, mix it with a bit more oil. You will get better lubrication and more power.

From my experience, (and I have plenty of it), if you're using any decent two cycle oil and the equipment is being run hard, there will be no issues with plug or exhaust fouling.

Don't get much easier than that.
 
Originally Posted By: boraticus

Mix the fuel at the manufacturers recommended ratio. Plain and simple.

Once again, the equipment manufacturer only provides the ratio for their own oil since that is what they want you to use. They can't possibly provide ratios for other oils since they don't know them.
 
It would only be logical to apply the engine manufacturer's recommended ratio for any oil. Otherwise, they would suggest following the oil manufacturers mixing ratios if using other than their specified oil (which I never use).

No need to complicate straight forward engine manufacturers instructions with oil manufacturers suggestions.

After all, do you think every oil company tested their oil on every brand/model of two cycle engine ever built?

Go with what the engine manufacturers know vs. what the oil companies think....
 
Quote:
the equipment manufacturer only provides the ratio for their own oil since that is what they want you to use.


Except that the manufacturer specs their 'own' oil-but that oil is conventional oil, and likely a middle quality oil at that.

A top line 2 cycle oil, not to mention a quality synthetic oil, would like work fine and a 'leaner' ratio.
Once broken in, a 40:1 machine could easily run at 50:1 with a better oil.
 
Originally Posted By: dwendt44
Except that the manufacturer specs their 'own' oil-but that oil is conventional oil, and likely a middle quality oil at that.

Well, Stihl recommends 50:1 ratio for both their mineral as well as synthetic oil (HP Ultra):

http://www.stihlusa.com/accessories/twocycleoil.html

I can't really attest to the quality of their oils. When I bought my leaf blower, the dealer gave me a 6-pack of their mineral oil, and I've been using it since then without issues. And that was 2 years ago, and I still have plenty of it left.
smile.gif
 
Originally Posted By: Quattro Pete
Originally Posted By: beanoil
NO NO NO! Mix at what the equipment requires, and recommends.

Sigh...

Read my response above.

I did. I disagree. What the equipment manufacturer recommends is a pretty safe bet. Especially in OPE and with the two stroke oils that are readily available at WM, as mentioned. Off the shelf two cycle oils are so similarly constructed, that you could pull any of them and be OK, as long as you get an oil that meets the specs of the manufacturer. If you want to get into a discussion on what constitutes a "better" oil for two strokes or the "less oil is better" vs. equipment life (or power produced) that's another topic.
Seems like everyone is on the 50:1 or 100:1 is better train. It's been proven time and again that two strokes make more power, and last longer when there is more oil in the mix, when jetted correctly . A two stroke gets a fresh charge of oil with every stroke. There better be enough there.
 
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