The fuel is not vaporized in the carb. It's in liquid droplet form. It doesn't vaporize until it encounters the heat from the engine.There’s a huge difference between liquid gasoline and the vaporized mix that comes in through the a carb.
mixing ratios for 2 stroke chainsaws
- Thread starter sawmill sam
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When your right....your right , very well summarized !
Not argumentative at all, but if a saw is cold and the fuel is not vaporizing completely, wouldn’t the oil in/and unvaporized fuel mix be going into the chamber? And burning (albeit incompletely)?
Yes, and because so little fuel is in vapor form the mixture is very lean and thus we choke the engine to flood it with even more fuel in the hopes we can get enough vapor to light off.
That's another thing. When we talk about fuel to air ratio. What we are talking about is the amount of fuel in vapor form vs the amount of air. Fuel has to vaporize to be combusted.
Highly atomized fuel will burn, like with modern fuel injection. Is this happening in the 500i when it’s cold?
Same thing I mentioned before max rpm and load determine proper ratio.
There’s a huge difference between liquid gasoline and the vaporized mix that comes in through the a carb.
So, you are trying to tell me that gasoline mixed with oil will not slick a cylinder wall up in a non running saw that I am trying to get loosened up any more that raw gas.
No, atomized liquid droplets will not burn..
Nothing special about a 500I in this regard. The injector set up on the 500 is a crude low pressure design anyways and just pukes out fuel like a carb. The only differance is the control factor.
Yes. Liquid premix has nearly zero lubricating properties.
Even in a 4 cycle trace fuel dilution in the oil degrades lubricating ability. Now increase that dilution many times over and you have pre mix.
Ok Im starting to see this... but gasoline doesn't burn blue, it burns black. So there IS oil getting to the combustion chamber. Residual oil from the crankcase?
If I were to pull the plug wire off my saw, pull it over a ton of times with a piece of tissue paper on the exhaust and tested it, there would be gasoline and no oil present?
Honest questions.... And this isn't basic stuff until I see that controlled experiment.
If I were to pull the plug wire off my saw, pull it over a ton of times with a piece of tissue paper on the exhaust and tested it, there would be gasoline and no oil present?
Honest questions.... And this isn't basic stuff until I see that controlled experiment.
sand sock
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The carboned up pistons that die from scoring from caking and falling off are from clogged spark arrestors. I run just shy of 50:1. 2.5 gal mix gets 2.495ish .
My 2008 Stihl 361. It's all stock, the cylinder is still clean. Mostly 30 cords a year. But have done up to 50. I am concious of how hot the saws getting. I try not to run out of fuel. I change the air filter every fall. I try not to cut when it's hot.
Maybe I should think about putting in a new oem piston. Maybe I am just trying to live life right. That my saw is lasting. Maybe it's because it's a prograde.
My little 562 . I can't believe how warm the saw gets while cutting. Maybe I need to pull the spark arrestor s to see if it runs cooler
My 2008 Stihl 361. It's all stock, the cylinder is still clean. Mostly 30 cords a year. But have done up to 50. I am concious of how hot the saws getting. I try not to run out of fuel. I change the air filter every fall. I try not to cut when it's hot.
Maybe I should think about putting in a new oem piston. Maybe I am just trying to live life right. That my saw is lasting. Maybe it's because it's a prograde.
My little 562 . I can't believe how warm the saw gets while cutting. Maybe I need to pull the spark arrestor s to see if it runs cooler
SOME fuel will be vaporized, even just sitting in a can in open air, at ambient temperature. You look closely and you can see the fumes; this is what makes gasoline so dangerous vs. diesel or kerosene.
Smaller droplets = more surface area = more vapor. While the atomized droplets themselves may not burn, the smaller droplets do contribute to there being more fuel vapor which will burn, and the smaller droplets will also vaporize more easily when subjected to heat. They'll fully vaporize faster than larger droplets for a given amount of heat, or fully vaporize at lower temperatures than larger droplets, in the same amount of time. All of this contributes to easier starting and less time on choke being necessary. It definitely helps.
LOL. I could just pour oil down the spark plug hole. But, usually I like to get them started sometime the same day.
The oil ends up getting burnt in the combustion chamber. The blue smoke partially combusted or uncombesyed gasoline and oil. A cold 4 cycle will do the same thing, only to a lesser extent for reasons inherent to the design.Ok Im starting to see this... but gasoline doesn't burn blue, it burns black. So there IS oil getting to the combustion chamber. Residual oil from the crankcase?
If I were to pull the plug wire off my saw, pull it over a ton of times with a piece of tissue paper on the exhaust and tested it, there would be gasoline and no oil present?
Honest questions.... And this isn't basic stuff until I see that controlled experiment.
You initially said the saw was advertised as not turning over. If that was the case I would put some two cycle oil down the plug hole.
Yes, that's all true. However the 500I is a low pressure injection setup and as such droplet size will be very similar.
With fuel injection you also have the option of really pounding the fuel to the motor, but cutting it off really quick, which a choke doesn't do.
That would also depend on if the saw was warm.Ok Im starting to see this... but gasoline doesn't burn blue, it burns black. So there IS oil getting to the combustion chamber. Residual oil from the crankcase?
If I were to pull the plug wire off my saw, pull it over a ton of times with a piece of tissue paper on the exhaust and tested it, there would be gasoline and no oil present?
Honest questions.... And this isn't basic stuff until I see that controlled experiment.
As for your expirement. It's pretty well known that solids and liquids don't burn..only vapors. This applies to even wood...
Could have. Mix did the trick just fine. Saying it has no lubricating properties when I can feel it immediately pulling it is some typical forum BS. I had an 036 that hadn't been run in years, and the owner was saying the bearings or who knows what else was out of it. I squirted some mix down the plug hole and had it running in 30 seconds. He wanted to know what I had done to it , and I said basically nothing.
I suspect if you would actually do some of this instead of being this cycles forum know it all might help you get a better grasp of the real world of making things run.
Interesting fact , that migration at idle can take as long as 10 minutes . Also that Maxima rates 60:1 for recreational riding . I will stay with my 40:1 ratio , oils a cheap insurance & a little xtra puddling within the crankcase & metal surfaces is beneficial in my opinion .
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