Fuel/Oil mix

[dang]

LOL, this is engine building 101 and I just cant believe it has not come up.

 

[Stumper]

Well Dang, I always use my screw turner to twist those slotty thingys on the gassucker dingus, so that it runs purty good with my oily gas.

 

[dang]

People are in here Recommending to other guys to run from 16:1 all the way to 100:1 and NOT saying a word about jetting changes that need to be changed to compinsate for this. Then you here of guys saying their motors are running hot- HUH Wonder Why?

 

[bwalker]

You cant idiot proof everything?

 

[klickitatsacket]

Hey guys. I build quite a few Modified Stihls. I reccomend 50:1 Stihl mix. I keep my RPM under 14K unless requested otherwise by the customers. I tend to favor high compression and high mix pressure to achieve desired HP gains. You can always put on an 8 pin sprocket if needed. Any how to the topic at hand if I need more lube I lower the back presure to allow more mix through. I have not had a saw returned under warrenty yet. Just my way of getting around the issue of lubrication.

 

[Stumper]

Dang, My humble apologies. The issue of carb adjustment with the mix being run is so basic and has been addressed so many times that it completely escaped my notice that it should be addressed directly in this thread ( I did imply it in a previous post). Most guys that are asking these questions for the first time are probably hesitant to attempt carb adjustments and are running a rich factory setting anyway.

 

[dang]

No need to apologize. I just feel bad when I have to help guys out rebuilding their motors. And all just because some guy they were talking to tells them some BS tuning advice and end up grenading their motor.

 

[Crofter]

I suspect that after a certain point the oill starts to be a greater part of the fuels burning characteristics instead of a lubricant. It doesn't all burn or evaporate. I have had occasion to swap mufflers and pipes quite a bit and have been surprised at the amount of goo and carbon I accumulate. I certainly am not idling my saws and the mixture is set to barely fuss at the edge of 4 stroking at no load. I am using synthetic at 32 to 1. Am tempted to switch back to Dino oil to see if there is a difference in this respect. Marky Mark made this observation about some synthetics a long time ago and I didn't believe him. I have used a number of different synthetics including Castrol, so couldn't pin it on brand. I also dont use a big total gallonage either so someone else that pulls down saws where they know what oil has been used consistently would know better. Curious!

 

[begleytree]

Ok,
'bout time to call BS.
No saw I've yet seen uses oil injection, like my boat engines.
At the most, your saw has a high and low setting adjustment, neither of which controls the amount of oil used by the engine. It only allows an amount of mix and air to enter the engine. The fuel/oil mix is controlled by the user.
now, rich=too much fuel mix, causing lower rpms in 2 stroke, also known as being on the safe side
and lean=a lesser amount of fuel mix, causing higher rpms, too much of a good thing can be bad
And too much oil causes heat buildup, carbon, sooting, ring sticking, and other known bad things.
now, as stated: 32:1 mix is 32 parts gas per 1 part oil. 50:1 is 50 parts gas per 1 part oil.
if you run 32:1 you are burning 1 oz of oil per every 32 oz gas. as far as rich/lean, you are running less fuel, (lean condition) with too much oil (which causes heat buildup) than with a 50:1 mix.
Now knowing lean and heat to be bad for 2 stroke engines, 32:1 would be very much more hazardous to your saw than the recommended specs of 50:1. You only have 1 fuel line from the tank, it only carries what you mixed and poured in the tank, the carb settings only control how much air is mixed with your fuel/oil mixture and sent to burn.

So anyone wanna tell me how adjusting a couple screws (that only control fuel flow, NOT mix rates) has squat to do with anything mix related (other than air/fuel ratios)?

My saws say H, L, and Idle. Maybe yours says H, L, oil and idle? If not, your carb does not control mix rates.

I'm sure this post won't be popular with you 32:1 guys out there, but you're gonna have to explain how carb settings mean anything to mix rates. -Ralph

 

[Molecule]

gas/oil ratio theories - but, which gas & which oil

So, here's what I learned yesterday from an independent tanker driver

except for one, all gas brands take their "main" fuel from the same "slug" in the pipeline. Then, when loading his delivery truck, he adds X-gallons of "additive." Shell gets the most- with 11 gals of Shell-brand additive per "tank" (a part of his tanker). Exxon, Mobil, Citgo, Sunoco, etc. all add 7 to 8 gals per tank, of their own special additives.

But, the main base gas for all the brands is the same.

The only brand that has its own gas is BP-Amoco Ultimate. When BP LBO'd Amoco, probably with the intent of shutting it down with debt fraud, a hardcore crew inside Amoco apparently added a contract requirement that BP always keep the Amoco Ultimate separate. At least that's what this driver said. So, when Amoco Ultimate is delivered in the pipeline, it comes in a "slug" which is separated from the other gas. He reports that Amoco Ultimate is just straight gas, no additives.

The Amoco Ultimate is clear white, and is 93 octane.

Stumper -- the owner's manual for the Dolmar 6400 says "The engine is designed for [*]unleaded [*]regular gasoline with a min. octane value of 91 [*]ROZ." Does anyone know exactly what "ROZ" octane means? Is it a european designation, exactly the same as our own (like meters and feet). I have to agree -- 91 octane is definitely not "regular"

It also adds that "Gasline which contens alcohol should not be used ... " And here is where my problem with the "new" fuels begins. I'm sure a good chemist, working on the Wall St. principle of profit by deception, could make additives which function exactly as alcohol-look alikes, and which would burn up our engines just like alcohol, without being "exactly alcohol."

As to ratio -- Dolmar suggests 50:1 with their oil, and 40:1 with competitors orl. In the next paragraph, they add , "...it is not wise to add more oil than specified ... fuel consumption will rise and performance will decrease. " Which translates to me as "Wow ... whenever I use the Domar oil at 50:1, it seems like my saw really comes alive ... better tell all my closest friends about that." I'm sticking with Mobil-1 (because the Madison Avenue sechsie light-blue colorization of the "other" oils exactly matches the color of their Viagra ... and I don't want any of that #!%& in my little engine ...), but I am considering a shift up to 40:1

 

[Crofter]

Begleytree; I think you are telling us that the gas to oil ratio is not the same thing as the air to fuel ratio. What is your stand on whether adding additional oil to a given amount of gasoline richens or leans the effective mixture?

 

[begleytree]

Crofter, a saw uses X-amount of fuel/oil mix to operate. the ratios put into the tank dictate what hits the engine. for every cubic centemeter of mix in the fuel line, a % of it is gas, and another % is oil. the %'s are dictated by mix rates. one side is 32 parts gas, 1 part oil the other side is 50 parts gas, 1 part oil.
At 32:1 rates, you are burning 1 part oil for every 32 parts gas. Thats a leaner gas mix along with a higher oil concentration, versus 50 parts gas to 1 part oil.
The statements have been made that all is equal because of carb settings. I disagree. I attempted to make my point that carb settings have no affect on fuel/oil mix rates, and feel that I did. If not, please point it out, and I'll try again.
All I'm doing is trying to make a point, trying to use as many examples as possible.
Like, say, I have 2 seperate glass jars, filled with one ounce of mix that I am going to run through my saw. One jar, at 32:1, my oz of mix has more oil, and less gas in it than does my other mixed ounce jar that contains a 50:1 mix. If I run these both out in the saw seperately, 1 at a time, at 32:1, I have run less fuel, and more oil than I did when I ran my 50:1 jar. During the time I ran my 32:1 jar, I consumed less gas, thereby run leaner, than when I ran my 50:1 jar. So adding more oil to the mixture leans the mixture, and adds something that cannot be burned to make power, at least in a saw,IMO. oil is there to lube the saw, none is bad, and too much, comes back around the same circle, and is bad.
Ralph, clear as mud

 

[ray benson]

All these theories and explanations. How do they fit with this???????
Sawracer works at a stihl-husky dealership here in california, they had a account that cut brush for PGE . they would buy ten saws at a time. first they lost almost all the big end bearings on the372 husky rods, then they bought 044 and 046 stihls and had piston/ barrels seizures. they finally went to 32-1 oil ratio and the problems were gone.

 

[Fish]

I just tried the teaspoon/torch test, but had some complications. I will try it again
for the site's sake, but next time I will go outside.

Also I will get my parts guy to do it, he is not married.

 

[begleytree]

All these theories and explanations. How do they fit with this???????
Sawracer works at a stihl-husky dealership here in california, they had a account that cut brush for PGE . they would buy ten saws at a time. first they lost almost all the big end bearings on the372 husky rods, then they bought 044 and 046 stihls and had piston/ barrels seizures. they finally went to 32-1 oil ratio and the problems were gone.

This post proves nothing, You heard it from someone who knows someone. Heresay, not admissable. What did these guys do to their saws? Who mixed the gas? did they run straight gas in it to kill some time and run to the saw shop? It happens, it did with my fathers company, guys get mad at dad, and run straight gas in the saw, then suddenly it was the 50:1 mix rate that done it in.
I'm not saying they didn't have problems, but you don't know all the circumstances either. I'd wager they thought they were mixing 50:1 but were really around 75:1, being off that far, switching to 32:1 in their case, with error figured in, puts them at what? 45-50:1. You say no problems since? sounds logical. All I'm saying is you or I neither one knows the facts here, so any assumption is flawed from the start, friend. -Ralph

 

[rupedoggy]

"Now knowing lean and heat to be bad for 2 stroke engines, 32:1 would be very much more hazardous to your saw than the recommended specs of 50:1. You only have 1 fuel line from the tank, it only carries what you mixed and poured in the tank, the carb settings only control how much air is mixed with your fuel/oil mixture and sent to burn."

Begleytree that above quote is yours and does prove something to me. You don't know how a carburetor works. The part of the carburetor that controls the "air" is the butterfly (choke also) not the carburetor settings.
If running less oil causes the saw to run cooler why don't we run none at all and have a real cool running machine? The answer is because we have no lubricant! The oil in the mix lubes the bearings in the bottom of the saw before it burns up top. The heat produced in a saw is dependant on the fuel/air ratio being burned not the oil content. You can fry a saw on any oil mix if you lean it out enough. Mike

 

[begleytree]

Rupe, so a carb doesn't control the amount of mixed fuel that is delivered? nor does it control how much fuel is added to the incomming air?
Then please tell me what does it do?
I'd wager you use 32:1, can't find flaw with what I said, so you jump me over a typo?
Did I type air? Once? did I really mean mix? Aren't you really splittling hairs?
I refuse to edit any previous post, If I erred in what I was saying, I own it. If I erred by way of typo, I claim that also. I've had to say it over and over so many times, that I'm sure any reasonable person would understand my humanity, realize what I meant, and went on.

So, if the manufacturer says 1 part oil per every 50 parts fuel is the idea mixture for their product, who are we to say different is better? Those stupid a55 engineers!!!
Tell me why I should use more oil than needed, when I know that more oil is more harmfull than good. Call me lazy, I despise having to tear down saws to clean mufflers and plugs. I also realize that plugs don't foul at once, that it takes time, all the while the spark is growing weaker, and the saw is loosing power, until it gets to the point that it won't run, and needs the plug cleaned.
Lets talk about the subject at hand, not about the fact Stumper smells like mixing oil after a long day and needs a bath , or wether or not I can really type. So many of these good discussions fall into the realm of you su(k ,they su(k, and that ends it all.
-Ralph
OH BTW (I will edit for this) I am so interested in this topic, thereby posting so much on it, because I am the one buying the saws for my company. I use/specify 50:1 mix rates, with no problems, BUT, if someone can convince me that more oil is better, I'll quickly switch to using those specs. I just haven't heard it yet. Maybe the info is out there, maybe it doesn't exist. I'd like to hear other opinions on it, backed by testing, logic or reason.
-Ralph

 

[tony marks]

i make this comment.. some on here are running modified worksaw like myself.. i use to run 50-1 stihl and think it did fine.. but in modified saws the power generated is gonna be a good bit more.. you will be asking that powerhead formore inevitably.. when ive got that thing opened up am am asking for more than the saw was itended to ever do.. ill opt for any better wear measures i can .. for that reason i go synthetic 32-1.. theres no smoke to speak of.. and no performance loss..yrs ago with dino mixes you would foul plugs doing different than manfacturer specs.. now the syns have eliminated that problem for me anyway..
so it depends i guess on what you gonna expect of your saw.when stumper is working i suspect his saw is being ask for the max.. so i think he an others
are just adjusting to what they are hoping will get them longer life.. thats what im doing.. when my adjustable carb saws are shot ,i wont enjoy the nonadjust saws.. so im doing everything i can to get the milage out of good pro type saws that i know and understand. mite not be much sawing left in me so i suspect my saws will out live me.i recommmend 32-1 mobil cause it works .. there plenty of others that do also..
ps i could be dead wrong ,wouldnt be the first time.. but this is my bet..

 

[bwalker]

Begley you are clueless and wrong in almost every instance so give it up. BTW my new snowmobile which is oil injected runs at about a 20:1 ratio when you do the math. The plugs are white and it runs very clean with smoke after its warmed up.

Frank, The goo you are notcing is a sign of poor oil, or you are not getting your engine up to peak temps. This could be caused by too rich jetting or crappy oil. You might want to try Esso easy mix or mx2t. I use EM all summer when I am up in Kenora and it works very well. I get it at Home hardware or Canadian wholesale.
If you are still burning dirty you need ot adjust you mix, or lessen the amount of oil you are mixing. Remember oil ratio and load go hand in hand. Limbing with a 660 would require much less oil than milling with one.

 

[begleytree]

Walker, My boat engines run 50:1, oil injected. Please prove me wrong. Clueless, How? Do you not understand that a tank can hold only a certian amount of liquid, no matter the mix rate? so per tank, with higher (32:1) mix rates, you are burning less fuel per tank?
clueless huh? I'll try to remember that. A quick reading of your post shows nothing other than "run it rich because I said so" Real helpfull
-Ralph