J.W Younger
ass kissing impaired
How does oil ratio affect fuel/air ratio. did a search but nothing turned up.
oil ratio
- Thread starter J.W Younger
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Lakeside53
Stihl Wrenching
Assume the oil doesn't burn. Assume you need say 13 to 1 air to gas for perfect combustion (both of these assumptions are slightly incorrect...
)
If your oil is 2% of your gas (50:1 mix), then you'll need to decrease your air (or increase the gas) by 2% of 13:1.. Change to 32:1.. you do the math..
)If your oil is 2% of your gas (50:1 mix), then you'll need to decrease your air (or increase the gas) by 2% of 13:1.. Change to 32:1.. you do the math..
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J.W Younger
ass kissing impaired
the way I do the math more oil will lean the air fuel ratio but I,ve been wrong before. anyway me and a friend were disagreeing about it.
spacemule
The Peanut Gallery
I thought 14:1 was optimal. . .
It is my understanding from conversations with two different Dolmar dealers that more oil in the fuel mix will lean the saw. If running a mix heavier that 50:1, the carb will need to be richened up a bit.
Sawdustmaker
Addicted to ArboristSite
13.995488397:1
J.W Younger
ass kissing impaired
that makes sense to me. If the oil doesn,t combust it will displace some of the fuel the air stays the same therefore the mixture is leaner.It is my understanding from conversations with two different Dolmar dealers that more oil in the fuel mix will lean the saw. If running a mix heavier that 50:1, the carb will need to be richened up a bit.
willsaw4beer
Addicted to ArboristSite
Yep, more oil means you have to turn out the screws...
Lakeside53
Stihl Wrenching
14.7 is in-theory the perfect ratio.. but... to quote Wiki...
"Naturally Aspirated engines powered by octane, maximum power is frequently reached at AFRs ranging from 12.5 - 13.3:1 or λ of 0.85 - 0.901."
willsaw4beer
Addicted to ArboristSite
Easy there Lake, all the alcohol in my brain is going to catch fire trying to think like that...
Lakeside53
Stihl Wrenching
boltonranger
ArboristSite Guru
But isn't it different than an air leak lean condition?
Interesting.
But I wouldn't consider it the same lean condition that occurs when you turn in your mixture screw.
You turn in the mixture screw and you've reduced the oil and the gas both.
If you up raise your oil ratio, you haven't increased air. Just added oil and reduced gas. Oil being the lubricant; it may have less power marginally but not less lubrication as would a classic air leak, no?
-br
Interesting.
But I wouldn't consider it the same lean condition that occurs when you turn in your mixture screw.
You turn in the mixture screw and you've reduced the oil and the gas both.
If you up raise your oil ratio, you haven't increased air. Just added oil and reduced gas. Oil being the lubricant; it may have less power marginally but not less lubrication as would a classic air leak, no?
-br
It is my understanding from conversations with two different Dolmar dealers that more oil in the fuel mix will lean the saw. If running a mix heavier that 50:1, the carb will need to be richened up a bit.
willsaw4beer
Addicted to ArboristSite
Aah, not as complicated as I thought. If I can understand it after the better part of a 12 pack it's pretty simple. All the numbers are a bit confusing but the theory is pretty straightforward.
spacemule
The Peanut Gallery
Does it have to do with how well the fuel is suspended in the air?
Dammit, just when I thought I was catchin on, now I gotta start all over.
willsaw4beer
Addicted to ArboristSite
Maybe because the air leak is air not mixed with fuel and oil?
willsaw4beer
Addicted to ArboristSite
I was wondering sort of the same thing. Does it have to do with the fact that the tolerances can't be absolutely perfect, and or does gravity have some sort of effect? I think it's getting to be time to concentrate more on drinking than thinking.
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