2 Stroke oil Mix question

[thatguy]

Over on another forum there is a post going on 3 pages discussing how to properly mix 2 stroke oil for use in 2 stroke, air cooled engines..

2 cycle oil mix - Page 1 - AR15.COM

I wanted to get your wisdom/thoughts on the idea.

The basic concept of discussion is one of two things..

1) Mix the oil/gas the per the package labeling and that mix is good for any 2 stroke machine (doesnt matter if the engine mfg says to run 32:1, 40:1, or 50:1). the idea is that the correct oil/gas ratio is not engine specific but set by the oil mfg, and adequate for lubrication for any engines..

the other belief is..

2) You must mix the oil only to what the engine mfg says (ie - if you have 3 engines and they all call for different ratios - you need to have 3 different gas cans, one for each ratio)

thoughts?

Brian

 

[hizoot]

I'm 54 yrs old. I've raced 2 strokes motorcycles since 1967. I still have a KTM 300 .When I was younger I raced motocross and that type of racing is basically a drag race from turn to turn (full throttle). We used 32:1 mixture ratio.

As I got older,I started racing more tight woods enduro and grand national cross country. The tighter the course,meant more finesse with the throttle and lower throttle openings. We used 45-50:1 ratio. If we didnt the engine would load up with too much oil and blubber and spew all kinds of black soot.

Rebuilding these bikes over the years taught me that oil/type does make a big difference as well. Jetting,air fuel ratio of the carb is a huge deal as well. The more oil,the leaner the mixture ...but the ritcher the oil is. The reason why its leaner with more oil is that the oil takes up part of the space of the gasoline.....the more oil,the less gas in any given air/fuel ratio. So the carb must be adjusted accordingly.

 

[Carl_NH]

I have a Husky saw 55 rancher, a Stihl 400 BP blower/fogger, and Echo trimmer and use one mix for all. Usually 40/42-1 and this seems to work well for all of them.

When I put too much oil in one time (30-1) the Stihl was much harder to start and smoked more. Lesson learned..

I run a season/summer on the same 16oz oil mix and try to stay with one brand.

 

[yomax4]

Also a good synthetic oil will help bridge the gap between motors with different mix requirements. Seems like the newer motors require less oil than the older ones.

 

[brucew44guns]

I once owned a Homelite Super XL12 saw. I recall it being a 16:1 mix.
Now, I have 6 different saws and blowers and trimmers that are all Stihl. I use the Ultra Synthetic oil at 50:1 for all those machines. One gas can, one fuel. The oil bottles are for 2.5 gallons of gas to be added. I usually put 2.4 just to give a tadge more oiliness. No way would I run that mix in that old Homelite.
I believe that when the machine builder says to go 20:1, or 30:1 or whatever, they usually are referring to Major Oil brands, or names of product other than their own. I used Union 76 brand oil for years, in my Stihls too, but always followed the specific recommendation, I think it 25:1 with major brand stuff, never 50:1 with an oil like that. Stihl say 50":1 with "their" oil, I think that's safe with theirs, but probably not with some generic Wal-Mart cheapo brand.

 

[oldyellr]

The correct answer is use the oil recommended by the manufacturer mixed in the ratio recommended by the manufacturer. That way you can't go wrong.

 

[284 International]

The correct answer is use the oil recommended by the manufacturer mixed in the ratio recommended by the manufacturer. That way you can't go wrong.

...Jetting,air fuel ratio of the carb is a huge deal as well. The more oil,the leaner the mixture ...but the ritcher the oil is. The reason why its leaner with more oil is that the oil takes up part of the space of the gasoline.....the more oil,the less gas in any given air/fuel ratio. So the carb must be adjusted accordingly.

In my view, these are the two complementary explanations. If you're going to run a different ratio of fuel to oil in your gasoline, you should be adjusting the carburetor. If you run the manufacturer recommended oil at their ratio, you don't need to adjust the carburetor jetting. (Altitude normalizing excepted)

 

[Bird]

I know in years past, I've had a 2-cycle motorcycle, boat motors, chain saws, etc. that may have recommended different mixes, but now all I have is a Stihl string trimmer and a Mantis tiller. Both call for 50:1 mix and I use Stihl Ultra synthetic. I buy the little 2.6 oz bottles, good for one gallon of gas, since I don't use it fast enough to keep a bigger gas can for my 2-cycle gas.

 

[LD1]

I think is actually more oil specific than engine. Because all 2-strokes operate on the same principals.

Older stuff called for richer mixes of oil becasue the oil just wasnt as good back then.

Technology has improved out understanding of oils and what they do. As a result, oils (especially synthetics) have gotten MUCH better at doing their job. As a result, a 50:1 mix of new stuff will lubricate as well as a 25:1 mix of old stuff.

Personally, we buy the 50:1 mix bottles that are supposed to mux with 2.5 gallons of gas. We mix them with 2 gallons, or about a 40:1 mix and werun that in everything, old and new.:thumbsup:

 

[ultrarunner]

I think is actually more oil specific than engine. Because all 2-strokes operate on the same principals.

Older stuff called for richer mixes of oil becasue the oil just wasnt as good back then.

Technology has improved out understanding of oils and what they do. As a result, oils (especially synthetics) have gotten MUCH better at doing their job. As a result, a 50:1 mix of new stuff will lubricate as well as a 25:1 mix of old stuff.

Personally, we buy the 50:1 mix bottles that are supposed to mux with 2.5 gallons of gas. We mix them with 2 gallons, or about a 40:1 mix and werun that in everything, old and new.:thumbsup:

My saw guy also recommends more than less... he said 40 to 1 is the way he runs all his personal equipment...

I've got some old stuff that is 16 to 1. Seldom run it... when I do, I go 16 to 1

 

[284 International]

Oils have gotten much better over the years, and less may be required to properly lubricate the engine. As Hizoot said, though, changing the amount of oil in the mixture affects the carburetor jetting. Running more oil than recommended makes the machine run lean on fuel. Running less oil makes the engine run rich.

So, if we restructure the question to ask "Is it ok to run my chainsaw rich on fuel?" (Less oil in the mixture) we would tend to say it won't hurt anything. If we were to ask "Is it acceptable to run my weed eater lean on fuel?" we would tend to say no.

To me, it seems less dangerous to use a better oil in lower amounts per volume of gasoline than it does to use a leaner mixture of fuel in my engine.

 

[roamerr]

The Mix % is only part of the equation. I had a KX250 years ago and the big no-no was mixing too much oil and gas. I was taught that it is stable for only a month or so. Eventually the gas takes the lubricity from the oil.

I use Mobil 1 2T (no longer made I don't think). I called Mobil 1 and they would only say that it is stable for a month. They did not recommend long-term storage of mixed oil and gas. I understand that Stihl recommends 3 month maximum mixed storage....

 

[JB4310]

I've got 10 different 2 smokes, from chainsaws to moped. I just do what Bird mentioned get a high quality one mix, one bottle per gallon, everything runs great, no smoke, no overheating.

How much can there be to discuss with mixing 2 stroke fuel

JB

 

[Bird]

The Mix % is only part of the equation. I had a KX250 years ago and the big no-no was mixing too much oil and gas. I was taught that it is stable for only a month or so. Eventually the gas takes the lubricity from the oil.

I use Mobil 1 2T (no longer made I don't think). I called Mobil 1 and they would only say that it is stable for a month. They did not recommend long-term storage of mixed oil and gas. I understand that Stihl recommends 3 month maximum mixed storage....

I'm certainly no expert myself, but the Stihl HP Ultra oil I'm using says it contains fuel stabilizers. However, I also add Stabil to my fuel and it says it keeps fuel fresh for 12 months. So, right or wrong, I just don't worry about it.

 

[ultrarunner]

I've got 10 different 2 smokes, from chainsaws to moped. I just do what Bird mentioned get a high quality one mix, one bottle per gallon, everything runs great, no smoke, no overheating.

How much can there be to discuss with mixing 2 stroke fuel

JB

Are any 16 to 1 and really old like 75 years?

 

[JB4310]

Are any 16 to 1 and really old like 75 years?

I don't pay attention to the ratios any more, but if that (16/1) is way off on the spectrum then probably not and no, none are 75 years old.
One is a 40+ year old homelite farm saw, seems to run perfectly, just a little loud

Are you saying the modern one mix's would not work in those examples?

JB

 

[oldyellr]

Are any 16 to 1 and really old like 75 years?

Good point. I remember having outboards that specified 16 to 1. Two-strokes have come a long way and I remember when ordinary ones were plain bearings while Mercury had needles, rollers and balls. I doubt if some of the antiques from the 1950s would survive running a 100:1 mix.

 

[ultrarunner]

I don't pay attention to the ratios any more, but if that (16/1) is way off on the spectrum then probably not and no, none are 75 years old.
One is a 40+ year old homelite farm saw, seems to run perfectly, just a little loud

Are you saying the modern one mix's would not work in those examples?

JB

I don't know... it a 1939 98cc motorcycle with a Sachs motor

I've never considered anything other than 16 to 1.

Just wouldn't want to risk it unless it was a sure thing.

 

[Furu]

I am a big fan of STIHL HP Ultra fully synthetic 2-Cycle Engine Oil. All my Stihl equipment calls for 50:1. I remember the old Homelite we had growing up (1960's) had a different ratio (40:1 I think) but can't recall exactly what it was. As far as stabilizers I think the HP Ultra does have stabilizers in it but I buy the HP Ultra in 1 gal jugs and mix 2 gals at a time. That will normally last me 2-3 days so I don't worry about it going stale. I definitely would not mix more than I thought I could use in a couple of weeks. The equipment will perform better and last longer with less maintenance if taken care of well.

 

[JB4310]

I don't know... it a 1939 98cc motorcycle with a Sachs motor

I've never considered anything other than 16 to 1.

Just wouldn't want to risk it unless it was a sure thing.

I understand your concern, with an antique like that. A modern mix would probably be to hot.

But 16/1 with what oil? I wonder if you could just richen up the mix by using more of the synthetic, say 2 bottles to a gallon. I would think that should cover the spectrum of any machine requiring more oil. still without excessive smoking.
Unless there is some reason those older machines would be negatively affected by synthetic.

JB.