Mix ratio -- observing the blue smoke

[North by Northwest]

More oil, leaner fuel to air ratio....

Yepper !

 

[North by Northwest]

Trust me I fully understand how oiling works on both 2-st and 4-st. Been racing motorcycles for almost 30 years. Blown up a few motors along the way. while The “new” oils are better, that is all I have ever run. They were new when I started racing. Unfortunately 2-st is a dying technology and there is not a lot of development going on except for decreasing emissions.
When people do oil migration testing with tracers, small bore, high rpm 2-st need lots of good oil. http://www.tlr-online.com/yahoo_site_admin/assets/docs/Maxima_Tips.61180056.html. Straight from the oil manufacturer. Another http://www.klemmvintage.com/oils.htm
one thing that probably saves our saws is they don’t make much power per cc. A 125 road race bike makes 40+ hp, a 80cc dirt bike makes 15+. Heck our 80cc saws wont make 7 without porting.

Your absolutely right 2 stroke technology is a dinosaur , unfortunately until electric battery technology increases were stuck with gas powered saws . Hell the new oils are amazing , I remember when mix oil & chain oil were a synonym . Sae straight 30 was used for both , talk about nuisance smoke !

 

[North by Northwest]

Let me ask you fellas this. When changing from 50:1 to 40:1 say, does the saw require re-tuning or is the ratio so small that it's not necessary?

The change is minute , when you go to 32:1 or 16:1 retuning is paramount since the additional oil will cause a leaner fuel to air ratio. Elevation changes or dirty restricted air filters or wear and tear (engine condition) routinely cause carb setting changes requirements . It really depends more within what type or class of oil you are using bro , never hurts to retune your saw in the cut if your not sure

 

[North by Northwest]

I normally see a little when it's cold, but after the tool warms up very little to none on my properly tuned machines with good fuel.
oil should burn fully in combustion with the fuel, and that means little to no visable smoke.
Smoke under full temp/throttle in newer saws means you're building carbon typically, bad oil type, or something else is out of whack.
I had a homelite super 2 given to me as a young teenager that blasted clouds of oil under all RPM and load at 50:1... it ran great for years off and on climbing, firewood, ect. 100's of hours, zero maintenance on my part, but had a leak between the carb and cylinder the whole time that caused me to tune it rich to compensate, hence the smoke.
I finally fixed it & it has never smoked since, not that I use it much.

Good post and catch on that issue bud !

 

[North by Northwest]

The previous AS people are correct as tune is important. For more than forty year have always run 34:1 especially my race engines and never plan on a change. With race motors carburation is a very specific tune set up for each RPM range. On Chain saw tuning it is a combination of H and L over lapping each other. Thanks

Right on Ted , good to see your still with us bud !

 

[North by Northwest]

I read that as two statements... "more fuel, more power" or "more oil, more lube" pick your poison.

Guess this is a 6 of 1 half dozen of the other if blue smoke doesnt mean proper lubrication. Based on what you guys are saying I suppose the condition of the engine after a given period of time is more an indicator of it being lubed properly or not rather than judging the blue smoke.

Back in the day when I was playing around with nitro RC's a healthy tune was indicated by still having a blue smoke trail under full throttle... suppose thats not the case with chainsaws.

Andy, is there a particular reason/incident you run 32:1?

Yeah , because buying oil by the barrel is Cool

 

[North by Northwest]

Generally, smoke comes from an excessively rich fuel/air mix. 32:1 won't smoke, if the tune is correct. With more oil, I do notice more "smell" from the exhaust.

Nitro RC engines run on a mix of oil, methanol and nitromethane. That requires a very rich fuel/air ratio for proper combustion (compared to gasoline), and to keep the ringless piston from seizing. Also, combusting methanol releases a significant amount of water vapor, which increases the appearance of "smoke".

More oil offers a few things...better ring seal, better protection of the moving parts when in use, and more left over oil inside the engine, to protect against corrosion during storage.

In your application depending on the oil type you use I would agree bro !

 

[Toyboy]

The change is minute , when you go to 32:1 or 16:1 retuning is paramount since the additional oil will cause a leaner fuel to air ratio. Elevation changes or dirty restricted air filters or wear and tear (engine condition) routinely cause carb setting changes requirements . It really depends more within what type or class of oil you are using bro , never hurts to retune your saw in the cut if your not sure

Stihl in either the silver or orange bottle. I'm not that fussy, but besides my saws I'm also using it in my Mantis, weed whackers, hedge trimmers etc.
In other words all my 2 stroke engines.

 

[husqORbust]

Getting pretty heated here... maybe I'll split the difference and run 40:1 and call it day and sleep easy since I'm not on synthetic oil.... thats about what I've concluded based on everything said. Lol.

 

[AlterEgo]

That's the smart choice.

 

[Andyshine77]

Getting pretty heated here... maybe I'll split the difference and run 40:1 and call it day and sleep easy since I'm not on synthetic oil.... thats about what I've concluded based on everything said. Lol.

40:1 is just fine. I find the ignore function does it's job when needed..

 

[OM617YOTA]

Learn to tune your saw, then tune it to whatever you're running. This is the far bigger issue, as there's a huge range of fuel to oil ratios that'll work just fine.......as long as you've tuned the carb for what you're running.

 

[ChoppyChoppy]

It has to do with how the saws carb is tuned much more than the mix ratio. I mix my oil @ 32:1 and only see a puff of smoke at startup, after that pretty much nothing.

Yup.

I have an older 2 stroke lawn edger with a carb that's fussy.
It'll nearly smoke out the neighborhood 007 style at times on 50:1 ratio fuel.

 

[Ted Jenkins]

A year or so ago a neighbor friend of mine gave me about a gallon or two of Yama lube and said hope you can find a use for it. I had been using Lucus Two Stroke oil which worked fine. At 34:1 it was just plain too too rich. I adjusted it until I was at about 40:1 or 42:1 which worked well. I would bet that I am one of the few people who can actually wear out a saw. Oil has little to do with how long a saw will give good service. I have a 041 that has been used for more than forty years and yes still running fine. The compression is notably on the weak side, but not sure I want to mess with it. It has cut 100 to 400 cords of wood and been up many trees. I have several Husky saws such as the 372 XP that can do every thing that the 041 can do so the Stihl will likely spend its last years on a shelf. The 041 has worked well with many different brands of oils through it and not complained. So a reasonable oil with a reasonable mix ratio will allow pretty much all two strokes to last as long as the OP. Thanks

 

[North by Northwest]

Getting pretty heated here... maybe I'll split the difference and run 40:1 and call it day and sleep easy since I'm not on synthetic oil.... thats about what I've concluded based on everything said. Lol.

If your running conventional mineral oil 40:1 is what I used for years , just ensure its designed for air cooled engines and all should fine bro !

 

[North by Northwest]

Stihl in either the silver or orange bottle. I'm not that fussy, but besides my saws I'm also using it in my Mantis, weed whackers, hedge trimmers etc.
In other words all my 2 stroke engines.

I bought Amsoil Sabre 10 yrs ago for the same reason , needed a Quality Synthetic blend oil and the price point was attractive along with the ethanol additive to protect my equipment from the corn fuel . It's getting harder to find ethanol free fuel recently , which sucks ! However was convinced to try some Maxima & Motul Product . The Maxima has been on sale here locally so I bought some this spring for my saws . 50:1 with all saws tuned in the cut same as with the Sabre previously .
.

 

[North by Northwest]

A year or so ago a neighbor friend of mine gave me about a gallon or two of Yama lube and said hope you can find a use for it. I had been using Lucus Two Stroke oil which worked fine. At 34:1 it was just plain too too rich. I adjusted it until I was at about 40:1 or 42:1 which worked well. I would bet that I am one of the few people who can actually wear out a saw. Oil has little to do with how long a saw will give good service. I have a 041 that has been used for more than forty years and yes still running fine. The compression is notably on the weak side, but not sure I want to mess with it. It has cut 100 to 400 cords of wood and been up many trees. I have several Husky saws such as the 372 XP that can do every thing that the 041 can do so the Stihl will likely spend its last years on a shelf. The 041 has worked well with many different brands of oils through it and not complained. So a reasonable oil with a reasonable mix ratio will allow pretty much all two strokes to last as long as the OP. Thanks

Agree 100 % Ted , All my saws even the vintage Pioneers and newest 576 xp & 5105 H run 50:1 with Premium Synthetic Oils . Originally in the 70,s with the conventional mineral oils I ran 40:1 continuously , no issues as long as you tuned your saw to the usage . I always tune my saws a smidge fat anyways just incase.

 

[North by Northwest]

40:1 is just fine. I find the ignore function does it's job when needed..

Try it more often when you pantyhose bunch up

 

[North by Northwest]

Learn to tune your saw, then tune it to whatever you're running. This is the far bigger issue, as there's a huge range of fuel to oil ratios that'll work just fine.......as long as you've tuned the carb for what you're running.

No truer words , have been spoken . Thank you Sir !

 

[North by Northwest]

More oil doesn't equal more carbon with proper tuning. In fact due to the dispersants in modern two cycle oil I see less buildup with more oil. Carbon is the least cause of failure I see in 2 cycle engines.

Bewildered was correct , Andre is partially correct , if everyone buys the Highest Quality & Priced Synthetic oil & tunes their saw to the oil usage. Unfortunately the casual saw owner listening to backyard hacks rather than the saw manufacturer & using conventional dino oils could run into Bewildered,s scenario eventually . P.S. Andre & holy cow I found the ignore button adio,s !