Too much oil in the mix will foul plugs, easy to fix. Too little oil in the mix and you risk cylinder/piston damage, expensive to fix.

A lot of the difference in mix ratios is from better 2 stroke oil. Good oil requires less of it.

I get rid of my older 2 stroke gas in my old truck, never had any issues from a few gallons added to plus 15 gallons.

You could add the correct amount of oil to a small fuel bottle to change the mix from 50 to 40 to 1 (that's what I would do).

I try and only use non-ethanol gas in the chain saw's.

https://www.chainsawsdirect.com/manuals/husqvarna_235e_240e.pdf

 

The 1964 all aluminum Homelite my dad lets me use has run on all types of mixtures and still runs great. Virgin piston.

My newer Stihl is a bit finicky and I only use the pre-mixed can fuel. Been a while since I used it because the Homelite is sweet.

 

The oil will usually have a suggested mix ratio. Use that. If the oil says it is made for 50:1 you are good to go.

 

If you use Opti 2 synthetic you can run in any ratio from 15-1 to 60-1. One jug is good for all your 2 strokes.
Jim

 

I’ve been using opti-2 for years in every two stroke I have, chainsaws, hedge trimmer, blowers, brush cutters, several different brands and different recommended mixes.
All run the same mix of opti-2 with zero issues.

 

I own an older Husqvarna model 235 chainsaw that is supposed to use a 40:1 fuel oil mixture IIRC. But, the Husqvarna web site now states they use a 50:1 fuel oil mixture - unless the owners manual says differently. I can not find my owners manual and I can not get it from their web site.

If the engine calls for 40-1 use 40-1. Attempting to use 50-1 mix will soon seize the engine due to lack of lubrication.

I recently purchased a Stihl model MS 261C chainsaw that is supposed to use a 50:1 fuel oil mixture. And therein lies the problem.

This requires me to keep two cans of fuel for chainsaw use. At the rate I use a chainsaw, I will either be throwing a lot of fuel oil mixture away, or I will be using a lot of old fuel.

You can mix a half gallon or a quart or even a cup. There is no law saying you have to mix by the gallon. Use the appropriate amount of oil for the amount of gasoline. If you are worried about longevity add a fuel stabilizer into the gasoline and mix well PRIOR to measuring out for your oil mixture.

I read that instead of throwing the fuel oil mixture away, I should just put it into my truck with a full tank of gas. Is that wise?

It will not hurt anything. You are talking about less than a couple ounces of oil in about 15 or 20 gallons (2000+ ounces) of gasoline.

Also, what are the real world consequences of running both chainsaws on the same fuel oil mixture? And which one would be the best one if permissible? Or, should I split the difference and run them both on a 45:1 ratio?

Do not use anything less than 40-1 in the older engine, and have a few extra spark plugs for the newer engine to replace them if/when they foul.

I do not want to harm either chainsaw by using an improper fuel oil ratio.

Thanks for any help you can provide.

:thumb: :thumb:

 

Thank you.

It seems my old mind was wrong about the 40:1 ratio. Both the Husqvarna and Stihl use 50:1. So, problem solved. Plus, learning to throw old mixture into my truck solves the problem of what to do with the old stuff.

Thank you to all who helped.

 

Also go to a lawnmower shop or motorcycle shop. Look for a device called a ratio rite. It looks like a two sided funnel. It's a plastic cup that measures how much oil for a certain ratio per gallon of gas. A cheap and easy wax to get the correct ratio for two strokes.

 

Another tip is that if you aren't sure of the ratio needed for your saw or anything else like that that has a small tank is to fill it with 50:1 and then add a capfull of oil to the tank. The worst that will happen is that you foul a plug like stated above, but I have never seen it happen even in new saws that are supposed to have the 50:1

 

I also have a husqv 235. I also have a stihl chainsaw and a husqv brush cutter.

I have acquired several 1 litre premixed fuel cans. I mix my fuel in the used up ones. I had one for 1:40 and another for 1:50.

I always use ethanol free gas.

As the years have gone by, recently I stopped making 1:40 for the one machine that uses it. I buy it premixed. Expensive, but I do not even use one 1 litre can per year. Runs like a charm, so it's worth paying a few more dollars, for the little use I give it.

1:50 I still make it. But my latest Stihl came with a large can of 1:50 fuel and run really smooth.

Am I the only one who fimd husqvarnas way easier to start than stihl? I do prefer the Stihl engineering, though. More solid.

Sent from my SM-A520W using Tapatalk

 

I run 40:1 in everything that way I'm cleaning plugs no replacing cylinders

 

I asked the Stihl service guy I deal with about his when I bought a new Stihl. It takes 50:1 but my old saw takes 40:1. He said the newer 2 stroke oil is synthetic and offers better protection then the old oil therefor you use less oil and get better protection, less pollution and less wear.

 

I run klotz super techniplate, a very good synthetic. I run 50;1 in everything. Stihl and echo.

 

I just purchased a non-professional pole saw from Stihl. If you use their pre-mixed gas or their two-cycle oil the warranty goes from 2 years to 4 year and they say it will run my other saws from echo and husqvarna. Seems to be a non-brainer choice.
I suspect the high compression saws have more critical requirements relative to the fuel.

 

the mix rate IMHO for the most part is a recommendation. it is like directions on things that have 10 different ways to make it work, but they have to pick something and put it on the package or in the directions as The Way to do something. general rule of thumb, if it is hot out, or you are going to really work that machine, run more mix in the oil for a lot of high throttle use. for a little casual work, trimming up a few branches once in a while, a little less mix in the gas may be the way to go. if the difference between 40 and 50:1 causes a two stroke to foul plugs, it has other problems bigger than the fuel it is running.

 

I know this is an old thread that hasn’t been responded to in a few years but I’m not sure there is a “ common gas/oil ratio” anymore. I could be wrong though.
As has been posted upthread Opti-2 is a pretty good universal option that works for me. I’ve got 2strokes that specify anywhere from 25/1 up to 50/1 and they all run well with Opti-2 and I don’t have to have several different ratios mixed for use. I’d guess I’ve been using it for over 10 years with no issues.

 

40:1 mix will not damage your 50:1 mix Stihl model MS 261C