40:1 instead of 50:1?

[beenthere]

StihlDoc I am getting confused as heck following this thread. I use Stihl oil that comes in the small bottles ( 2.6 oz I think ). I mix it to one gallon of fuel. Could you tell me if I am right in doing so. I run this mix in my Stihl 026 Pro winter and summer.

UR doing it right. Says right on the bottle that it is to be mixed with 1 US gallon of fuel (I use premium as it doesn't have ethanol in it).

[Rocky_J]

when all else fails, read the directions on the label...  :

[Todd]

Its all so clear now!!??? ;D ;D ;D

[bwalker]

In the USA, the percentage of bright stock was changed and the treat rate and chemistry of the additive also changed in 1989 when the mix ratio recommendation and bottle

Which is a the same approach that was used in the early 80's.

[StihlDoc]

Run what your instruction manual states or whatever ratio and brand of oil you are comfortable with and have confidence in. If you elect  to use something different than a manufacturer recommends, don't complain that the product is not up to standards if you happen to experience lubricant or combustion deposit related failures in the future.

The amount of oil to gasoline in the USA to achieve a 50:1 ratio is:

1 gallon gasoline to 2.6 ounces oil
2.5 gallons gasoline to 6.4 ounces oil
5 gallons gasoline to 12.8 ounces oil

Items to note for small air cooled two-stroke engine lubrication:
a) Small changes in mix ratio won't be noticeable to you or the engine (e.g. 40:1 vs. 50:1).
b) Higher mix ratios (e.g. 50:1, 80:1, 100:1) allow the engine to produce more power as long as the oil has the necessary lubrication properties to overcome friction.
c) Don't run outboard motor oil in high performance chain saws and don't use high performance chain saw oil in outboard motors.
d) Synthetic oils are usually better performers than petroleum oils.
e) Manufacturers do extensive testing to come up with an oil formulation and mix ratio that has a reasonable price and works well in their products under most circumstances.

[bitternut]

Thanks, I will continue as I have been at 50:1 with Stihl oil.

[clyde]

stihl-doc
why do you get more power when running less oil in the mix?
I don't believe this to be true.
testing has shown us that a two-stroke motor makes more power with more oil in the mix all the way until the spark plug will foul.

[StihlDoc]

The BTU energy in gasoline creates power. Oil is not as volatile and does not produce the heat energy that gasoline does. But oil does reduce friction and helps piston rings to seal. It is possible that you could feel an increase in engine power by adding more oil if the engine cooling is not efficient, the piston/cylinder tolerance is tight, or piston rings are worn.

[bwalker]

Mac authored a SAE paper int he 70's that conlcuded that a two stroke made more power as the mix ratio was decreased up untill plug fouling became a issue.

"The BTU energy in gasoline creates power. Oil is not as volatile and does not produce the heat energy that gasoline does. "
Wouldnt oil have a higher BTU than gasoline and it sureley produces heat energy when it burns.

[clyde]

Mercury outboard motors came to the same conclusion also.
It really doesn't matter what the btu's of the oil is.  It is really not burning in the cumbustion(not much anyway).  This is why the engine runs leaner with a higher oil ratio (less gas mixed w/same amount of oxygen).  The oil volume isn't even figured in because it is not burning.  Most of the oil is burned off in the muffler.  The increased power (dyno-proven time and again) is more due to better ring sealing (higher compression) than less friction (not a bad thing).


****32-1****

[kkesler]

What would the consensus be on the appropriate mix for my Homelite C-5 with modern oils?

Here is what it says on the saw:
Off site photo link deleted by Admin, refer to rules posted at bottom of every page.

(16:1)

[Gypsy7]

with the ratio of mix of 50:1 is what oil to fuel in ml and litres please and also 40:1 ratio mls of oil to fuel. I worked it out at 25ml oil to 1 litre of fuel and 20ml oil to 1 litre of fuel is that correct :

[dougand3]

20 ml to 1 liter for 50:1
24 ml to 1 liter for 40:1
is close enough.

[joe_indi]

with the ratio of mix of 50:1 is what oil to fuel in ml and litres please and also 40:1 ratio mls of oil to fuel. I worked it out at 25ml oil to 1 litre of fuel and 20ml oil to 1 litre of fuel is that correct :

50:1 is 20ml per liter and 40:1 is 25ml per liter. Simple method is to divide 1000 by the first number in the ratio.
Here in India Stihl and Makita oils are available.
Also Indian brands from the fuel companies. The Stihl oil is used at 50:1(20ml/liter) and the Makita at 30-25:1 (30 to 40 ml/liter) and the Indian brands at 25:1.
All that on standard setting.
When leaning out to ensure the saws dont starve for lubrication at our tropical temperature it is the normal practice to increase the oil by a few ml. With a lean burn and extra oil we dont get black carbon buildup. More of a dark to light gray exhaust, cylinder top and piston top.

[sawguy21]

What would the consensus be on the appropriate mix for my Homelite C-5 with modern oils?

Here is what it says on the saw:
Off site photo link deleted by Admin, refer to rules posted at bottom of every page.

(16:1)

I run 50:1 in my old saws, I have yet to fry one although they don't see much use. Just make sure you properly adjust the carburetor. I had a C-5, what a beast. It would take a bigger man than me to pack it around all day.

[Thomas Lilli]

With regard to mix oil, I'd suggest you would have to know more about mix oils. Flash points are all over the place, and film characteristics vary greatly per degree of temperature from one oil to the next. Synthetic vs mineral etc. 

I also understand that, because of the environmental considerations, manufacturers make design changes that make them run, inherently hotter (intake air stratification vs exhaust stratification) and therefore leave a larger range of fit between piston and cylinder compared to saws of 10-15 years ago. This all comes into play when you contemplate mix oils in my opinion. 

The man that builds my saws recommends a 50:1 full ester synthetic mix oil and he's done extensive tests with those oils as a pro northwest faller and builder. My saws are designed to run on highest octane possible, Motul 800 2T factory line road (or equivalent) mix oil at 50:1. They're obviously high compression and the 461, revving a bit higher than factory. He builds them for falling and, the amount I cut per year, I'm sure they outlive me.  

Incidentally, I pulled the plug on my 461 just to borescope the cylinder and everything inside was pristine, not a mark on the cylinder. The piston top only had some erosion marks from gas flow at the intake and exhaust ports. 

Good discussion. 

[Al_Smith]

The resurgence of a 15 year old thread concerning the great oil debate . 8) --gotta luv it ---

[Old Greenhorn]

Some horses won't die no matter how hard you beat them. ;D

[Reddawg]

I was a Stihl Ultra 2-cycle oil user while my 461R was under warranty. Found 50:1 to leave some deposits on the piston and exhaust. Nothing major but it's new so I wouldn't expect much either.
Switched to a recommendation from a pro saw builder and faller of big wood, Motul 8002T at 42:1, since 3oz per gallon mix in the field is easy to do. After a bit of fine tuning from the factory setting, I see a better burn of the fuel mixture with the piston cleaning up and the plug dry and slightly brown on the electrode. 
On the big saws and the small ones I run the same mixture with 89 gas that has ethanol in it. No place close to get pure gas. I don't have any issues at all, knock on wood, and would recommend a bit more lubrication than less. These saws work really hot in the hardwoods so be kind to the saw and it will reward you for a very long time.

[Canuck123]

Definately Gotta love , the oil ratio threads . I agree with Stihl Doc & Saw Guy that 50:1 with modern synthetic oil will protect today's & yesterdays saws . It's simple ,  improved oil technology . Mr Walker is correct within proper tuning and xtra oil can improve horsepower in racing scenerio's however in the hobby woodcutter life may cause additional carbonizing of the exhaust ports and piston rings . This is due to lower operating temps of consumer saws vs professional saws with high compression and rpm operating ranges. I run Sabre & Motul T at 50:1 on most applications , in certain saws I run 44:1 while milling or bucking . Anyhow good discussions , long live the oil threads !

[barbender]

You love oil threads so much you had to drag up one from a year and a half ago?😁

[welderskelter]

I was out of gas in the mill yesterday and all I had was chainsaw gas. So my 17 hp. kohler runs good at 30 to 1. I was surprised it didnt even smoke. Which reminds me I should lean it out on oil now that I got some more gas. I can remember when I was about 16 dad had a remington and I had an old mono. We bought our oil in town as bulk oil. Dad bought a 2 gal. can of hydraulic oil. When we needed some for the tractor we figured out we had used it all up for the chainsaws. Dont know that it hurt them any.

[Canuck123]

You love oil threads so much you had to drag up one from a year and a half ago?😁

Hell , would you prefer from 10 yrs ago ? Actually  , enjoy the various opinions !  8)

[Canuck123]

I was out of gas in the mill yesterday and all I had was chainsaw gas. So my 17 hp. kohler runs good at 30 to 1. I was surprised it didnt even smoke. Which reminds me I should lean it out on oil now that I got some more gas. I can remember when I was about 16 dad had a remington and I had an old mono. We bought our oil in town as bulk oil. Dad bought a 2 gal. can of hydraulic oil. When we needed some for the tractor we figured out we had used it all up for the chainsaws. Dont know that it hurt them any.

I would like to see how one of the new computerized saws would react to straight 30 @ 30:1  :D

[barbender]

I think they would get confused😂