My weed eater (Craftsman) asks for 40:1 mixture of gas to 2 cycle oil. My chainsaw (Husky 18") wants 50:1 ratio of gas to oil.

Do I need to maintain two different mixtures, or will one mixture at 45:1 work for both? What are the downsiders and tradeoffs using one mixture? I use the weed eater about once a week, and almost never use the chainsaw. Odds are any one gallon mix for the chainsaw would go bad (gell) before even three quarters of it got used.

What say Arfcom experts?

Use 40:1 for both.

Mixture is oil specific. What ever oil you use, it will say what the mixture should be.

Bad advice. Too much oil, means too little gas. It will run lean. Follow the mix ratio on the oil bottle.

Mixture is engine specific.  Whatever oil you use, check the manual for the proper mixture in that engine.

2-cycle oil is 2-cycle oil.  There's no "40:1" oil or "50:1" oil.

Wrong. There are some oils that are 100:1.

...but what do I know.

ETA: Mix this at 40:1, and you will have serious problems.

http://www.willardssmallengines.com/shop/lubricants-cleaners/lubricants/20112-opti-2-2-cycle-engine-oil-34-oz-.html

Get a can of concentrated oil from Lowes etc. Read the can make sure they recommend a 50;1 mix. Mix at 50:1, use in both units. The difference between 40 and 50:1 is maybe a quarter oz. in a gallon.1 gallon=128oz. Do the math.



If you want add a teaspoon of oil in the weedeater tank then fill with 50:1. Add stabilzer to all fuel summer or winter.



Get spare NGK spark plugs for both units. Swap and clean if you foul a plug.

I went to Lowes today to get some 2 cycle oil. They have a brand that comes in a 2.6 oz shot that you mix in a gallon of gas. Supposed to cover you for everything from 16:1 to 50:1. Works great in my 40:1 Weedeater string trimmer.

no, that stuff is a joke.



trust me ive worked with small engines for years and years and there is no cure all for 2 stroke mix ratios.

buy the premium oil and follow what the manufacturer recommends. if they state 40:1 use a 40:1.



if you use too much oil you can cause oil to build up and "cake" to components. if you dont use enough you can cause wear due to lack of lubrication.





 

Both the HP, and Ultra are great oils. The Ultra smokes less, lubricates better, and creates less carbon build up (very important in the new 4-mix engines).

the new synthetic oils do smoke less and are suppose to run cleaner but after tearing down saws that have run on both i have not seen much of a difference.



like i said before stick with the high quality brand name oils, ex. husqvarna and sthil. those 2 brands are great oils that when mixed correctly will make your saw run great and last a long time.



 

Well, I feel better.....now that we've cleared this up.....

Follow the ratio the engine requires is best.

The bottles are normally just sized to make the correct ratio (though when you hit 100:1 the oil itself is different.


The difference between 40:1 and 50:1 is not enough to matter as long as you meet the 40:1 for those engines needing 40:1.

The 50:1 will do just fine on 40:1 oil.  The amount is not enough to have any real effect on mix and lean the engine.

The grade of fuel and age of the fuel would have a greater effect.

A 2 cycle engine, is a 2 cycle engine. Same type bearings, rings, etc. The difference is in the oil.

I've been doing this for a living all my life.

So a steel sleeved engine is the same as an aluminum?

Don't think so.

They would all use 100:1 then.

You are invited to take  a 40:1 engine and try it on 100:1 oil for a few tanks and check the wear (if it lasts that long).

Aluminium cylinders still have a chrome plating. Yes, as far as lubrication goes, the cylinders are a little different, but all oils on the market meet the minimum lubrication requirements..

As far as the 100:1 thing, I have done extensive testing on this, along with Stihl. We ran every oil on the market, at the oil specific mix ratios. No engine failed due to lack of lubrication. After abusing these engines for 50 hours, we tore the engines down. Some of the engines showed more wear than others. The engines that showed the most wear, were the ones we used cheap 40:1 oil in. The Opti2 100:1 oil works great in all 2 cycle engines, even the older 32:1 off road engines.

Idaho has laws in place requiring ethanol, but there are some stations that have ethanol free fuel. Ethanol is the leading killer of power equipment. I do believe that the pre-packaged fuel does not contain Ethanol.

Does premium have ethanol in your ao?
Also ask boaters as they might know where to get the ethanol free gas.

Most hardware stores have it.

Are you familer with the Cycle magazine article by Gordon Jennings? It was back in the late 70s. He took a Suzuki PE250 air cooled motorcycle and put it on a dynomometer and tested premix ratios. He stuck with one oil and tested hp and wear. He also put a tracer in the oil and monitered how long it took for the oil to work it's way through the engine. It took appox 1/2 hour for the oil to travel completely through the engine. What he found was that the richer mixtures 16:1 provided the most horsepower and the least wear. Jennings thought it was due to increased compression.



Gordon Jennings also preferred castor bean based oil due to it's tenacity in sticking to the bearing metal. He said you almost had to machine it off. Maxima makes a blended castor supplemented oil called Castor 927. It is a premix oil as has the added perk of smelling great especially with race gas.
"There's nothing like the smell of race gas and bean oil in the morning"




Jennings was an engineer and did other research and prototype developement. He wrote a book called Two Stroke Tuning For Performance which was a very good read.



PJ1 oil also has done studies on mix ratios and performance. Torco is another brand that I think mixes their own oils and additives.



My own experiences are that having plenty of oil will make the engine run reliably. Thirty weight non-detergent motor oil can be used in a pinch. I had a 67 Montgomery Ward/Benelli motorcycle that recommended it. If you put detegent oil in it it would "whisker" the spark plug gap and require removing and cleaning the spark plug.



2 strokin' from 1971. 51 years young now.

Better check on that.

Chrome does not stick to aluminum worth a damn.


The trick is to use aluminum with a decent carbide content.
Everything wears away leaving carbide on the surface.
The rings are chrome plated.

The rings are Chromoly, the cylinders are a Nickel/Chrom plating.

Old school, I like it.

I ran 927 in all of my race bikes.

Mmmmmmmmmm........bean oil at the Supercross in an enclosed stadium.......mmmmmmmmmm good shit.


Of course you buncha young fellas have that 'synthetic' stuff.  No wonder obama is president

Mix that with VP C12, and it's a beautiful thing.