Who's Good At Math ?

[billt]

I have a older Homelite XL chainsaw that runs on a 32-1 gas/oil mix. I like running the Tru-Fuel, but the 32 ounce bottle I have is pre mixed at 40-1. My question is how much 2 cycle oil would I have to add to a 32 ounce bottle of 40-1 mix, in order to increase the mixture to 32-1? Thanks in advance.

[tombogan03884]

To bad it's not the same as the ratio of gin to tonic, This crew would have it down pat.   

[billt]

I'm figuring in a 32 ounce bottle of 40-1 mix, there are 0.8 ounces of oil. So if I added an additional .2 ounce, (say a 1/4 ounce to be safe), that would bring it up to 32-1. Because 1 ounce of oil in 32 ounces of fuel = 32-1. But my mind has gotten lazy since I retired.

[Solus]

I say .25 oz.

32 to 1   is 8oz to each .25 oz.   

so going from 32 to 40 is adding another 8oz..which would need another .25oz

[tombogan03884]

I had a Super XL before I went in the Marines.
Good saw back then. To much oil will make it smoke, to little will cook the motor, I think your math is close enough, but like you I've gotten lazy.

[Sponsor]

[alfsauve]

I want to go back to the gin and tonic

[Rastus]

Premix?  Add 0.8 ounces and call it good. 40:1 would be 25% less and 20% more is looking at it from the other perspective.  0.64 may be right on...but a little more won't do more than cause you to clean a fouled plug.

[tombogan03884]

I want to go back to the gin and tonic

See what I mean.   

[TAB]

Me i got my degree in math.


So let me break it down.

A 40:1 mix has 1 once per 40 oz of gas.  So you take 32 and divide it by 41. ( remember 40 :1 mix is 40 oz + 1 oz)  So you have .78 oz of oil in that bottle.  You would need to add .22 oz.


All this is assuming you mix the oil and gas perfectly.  There are 2 table spoons per oz so if you add 1/2 table spoon of oil you are good.
So the quater oz is correct.

[billt]

Me i got my degree in math.


So let me break it down.

A 40:1 mix has 1 once per 40 oz of gas.  So you take 32 and divide it by 41. ( remember 40 :1 mix is 40 oz + 1 oz)  So you have .78 oz of oil in that bottle.  You would need to add .22 oz.


All this is assuming you mix the oil and gas perfectly.  There are 2 table spoons per oz so if you add 1/2 table spoon of oil you are good.
So the quater oz is correct.

Thanks TAB. I'm thinking of getting one of those plastic syringes at the drug store. (The kind you use to get liquid medicine down a dogs throat). They are graduated in CC's and ML's. So I would have to convert ounces to both of those. But it would be easier and more precise.

I wish I knew the exact capacity of the fuel tank. (I downloaded the owners manual, but it doesn't have it). That way I could treat it by the tankful. This saw doesn't get run a lot, and all of my other 2-cycle stuff is modern Echo, (power blower & gas hedge trimmer). And they both run 50-1. I use 40-1 just to give them a little more lube. This 50-1 stuff is all brought on by the government, and the EPA because of emissions. Not for the betterment of the engine. Just like using all of these water thin oils in the new cars, to boost their fleet mileage.