mixing ratios for 2 stroke chainsaws

[tfp]

We should cover what brand of oil needs to be used just so we're all on the same page

 

[grizz55chev]

We should cover what brand of oil needs to be used just so we're all on the same page

Lol, good luck with that!

 

[camel2019]

I run 32 to 1 with all my equipment and tune it for my mix so far seems to be working well and I have the piece of mind that my old saws are getting oil as well as my new equipment.

And as far as oils go stay away from Stihl and outboard oils and you will be fine.

 

[benz66]

Ug! Another oil thread! But since it is going.... I'll ask my poulan question. I inherited a Poulan 305 Pro and 220 Pro. They are both about 20 yrs old. The 305 says right on the saw to run 16:1! I didn't think anything but a 1960s or earlier outboard, or the even older McCoullghs ran 16:1. Is 16:1 really the right mix, or do most folks use a 32:1 or other ratio with these saws?

 

[MacAttack]

Ug! Another oil thread! But since it is going.... I'll ask my poulan question. I inherited a Poulan 305 Pro and 220 Pro. They are both about 20 yrs old. The 305 says right on the saw to run 16:1! I didn't think anything but a 1960s or earlier outboard, or the even older McCoullghs ran 16:1. Is 16:1 really the right mix, or do most folks use a 32:1 or other ratio with these saws?

16:1 was used when those old saws (like my PM270) ran on straight 30 or 40 weight motor oil mix (and somehow didn't immediately seize and burst into flames).
I run all my vintage saws 40:1 with Echo Power Blend and they love it.
Do not mix 16:1 with modern oil, you'll just kill mosquitoes.

 

[camel2019]

Ug! Another oil thread! But since it is going.... I'll ask my poulan question. I inherited a Poulan 305 Pro and 220 Pro. They are both about 20 yrs old. The 305 says right on the saw to run 16:1! I didn't think anything but a 1960s or earlier outboard, or the even older McCoullghs ran 16:1. Is 16:1 really the right mix, or do most folks use a 32:1 or other ratio with these saws?

16 to 1 is a mix for non detergent 30 weight oil or really old simple 2 stroke oils(that were basically 30 weight). I’d run it at 32 to 1 with a modern 2 stroke oil and tune it for the mix.

 

[J D]

I've forgotten more than you'll ever know about chainsaws and oil.

Alzheimers?

 

[Dennisthemenace]

Adding more oil displaces a small amount of fuel in the air:fuel mix... less fuel means slightly leaner = slightly hotter & higher rpms. Small changes like oil brand (yes a different brand/type of oil can make a difference too) or slightly heavier mix ratio aren't usually significant. Problems occur when a saw is tuned on the lean side already & a change pushes it over the cusp of meltdown.
My recommendation is to tune for the conditions & the mix you are running.
When choosing a mix, bear in mind that a lack of oil kills thousands of times more motors than carbon build up, & while oil has come a very long way, it has become leaner over time primarily for environmental reasons over equipment lifespan.
Dammit... here we go....

Ahh, a nice little oil thread, you bewdy

 

[Hermio]

I recently had a conversation about mixing ratios for 2 stroke chainsaws and I would like to hear more opinions about it.
I have watched 2 you tube videos that confirm what I have always thought, that more oil causes more heat because it burns hotter than gas.
Here is a link to one of the videos I watched on this subject (by Dave's small engine channel) and I would like to hear what our experts have to say in this forum about this video.
It is a simple and effective method to prove my point that heat levels increase when more oil is used.



thanks in advance and sorry if I'm beating a dead horse here!

My first chainsaw used a 16:1 ratio, and the exhaust fumes were awful. Oil technology has improved to the point where 50:1 is fairly typical today, and some oil brands claim 100:1 is doable. The key is to have enough oil to create an oil film on all the parts. More oil than that just blows out the exhaust; it does not improve lubrication. For me, I stick with a good synthetic oil and a 50:1. 100:1 may work with some oils, but I have no way of testing for oil; film thickness, so I am willing to waste a small amount of oil rather than risk my saw. But 50:1 has been in general use for at least 20 years and the saws have run just fine.

 

[grizz55chev]

Alzheimers?

Not yet, I keep my self busy repairing antique machines of all kinds my shop is full of anything from generators to boat motors. My 34 Elto Pal 1.1 hp.

 

[Vintage Engine Repairs]

If he’s not turning the saw for each mix, more oil = less fuel = running lean which would make it run hotter.

That’s not true, oil ratio has no noticable affect on the engine running lean or rich. Oil is a fuel.

 

[OM617YOTA]

That’s not true, oil ratio has no noticable affect on the engine running lean or rich. Oil is a fuel.

This isn't a hard and fast rule, I've had it change the tune on me. We've been over this before.

Know how to test the tune of your equipment, and tune for what you're running, whatever that may be.

 

[sawmill sam]

I run 40-1 or 32-1 however it gets poured, adjust carb as needed before starting to cut due to temperature changes. More oil ='s better sealing capability of the rings raising compression, not necessarily a larger volume of oil retained in the bottom end but the oil retained is exchanged for new oil from the fuel supply more rapidly. Saws use fuel and the fan for cooling, oil ratio has such a tiny impact on temperature it does not even matter compared to lube, sealing and cleaning capabilities.

"oil ratio has such a tiny impact on temperature it does not even matter compared to lube, sealing and cleaning capabilities."

Your sentence above clarified best what I was wondering about most when I posted the thread.
I thank you for your insight

 

[huskihl]

That’s not true, oil ratio has no noticable affect on the engine running lean or rich. Oil is a fuel.

It definitely can make a noticeable difference.

 

[sean donato]

My first chainsaw used a 16:1 ratio, and the exhaust fumes were awful. Oil technology has improved to the point where 50:1 is fairly typical today, and some oil brands claim 100:1 is doable. The key is to have enough oil to create an oil film on all the parts. More oil than that just blows out the exhaust; it does not improve lubrication. For me, I stick with a good synthetic oil and a 50:1. 100:1 may work with some oils, but I have no way of testing for oil; film thickness, so I am willing to waste a small amount of oil rather than risk my saw. But 50:1 has been in general use for at least 20 years and the saws have run just fine.

Can't remember if it was yamaha or which bike manufacturer tasted oil ratios to power levels, the more oil they added the more power the bike made. Can't remember where the cut off was where they started loosing power and sending splooge everywhere out the pipe but it was a pretty heavy ratio.
We've been over this too, but I guess I'll give the short version of a pass through lube system and predominantly what dictates mix ratio. Rpm and load. Higher rpm, the lube passes through the engine faster more oil is needed. High continous loads need more lube oil as well. Even moderately ported saws arnt considered high performance, rpm, or high load engines. Really they are pretty low performance compared to their non emmission counterparts so moderate oil ratios are typically recommended.

 

[sawmill sam]

More oil can = more heat. But not because of less gas in the mix.
This is how I see it, with a heavy heating background (primary oil heat) as well as a heavy snowmobile background, where serious drag racers measure BTU value and adjust clutching and jetting accordingly.
Mix oil is a higher BTU/gallon than gasoline, so having more of it in your mixture is going to mean your mixture has more potential energy.
This is always going to mean that for the same volume of mixture consumed, there is more potential heat in said mixture.
We all know that some of that oil in the mix drops out of suspension and stays in the bottom end; and not all of it is burnt completely so the increase in heat with increased input BTU isn't going to be as direct as it is in heating, but it will be there nonetheless.
At the same time, richer air/fuel is still going to be colder and lean hotter, that isn't going to change.

"Mix oil is a higher BTU/gallon than gasoline, so having more of it in your mixture is going to mean your mixture has more potential energy.
This is always going to mean that for the same volume of mixture consumed, there is more potential heat in said mixture."

I took this quote from another thread. So, on one hand, my thinking about oil=heat was correct but I was incorrect in thinking that it noticably affected running temperature if you adjust the carb to compensate for the leaner condition . Thanks to all for your input and I hope everyone's winter will be mild!
ps. feel free to agree or disagree with my conclusion!!

 

[Lightning Performance]

It definitely can make a noticeable difference.

Have you been affected? We did actually meet,

 

[OM617YOTA]

Can't remember if it was yamaha or which bike manufacturer tasted oil ratios to power levels, the more oil they added the more power the bike made. Can't remember where the cut off was where they started loosing power and sending splooge everywhere out the pipe but it was a pretty heavy ratio.

I remember it being 25:1.

 

[sean donato]

I remember it being 25:1.

Sounds about right, it was pretty long ago they did it. My mind is like a sieve these days...

 

[Lightning Performance]

Absolutely zero point running 25:1 with a good quality synthetic mix oil. 32:1 is the heaviest I would go and only for a milling application. 40:1 is what I prefer for general use.

Depends on the weather I'd say.
Humidity and ambient temps matter.
32-1 burns in my big saws on the mills in weather that is dry and above 80*F
32-1 pours out the exhaust around 50* with high humidity.
32-1 ain't worth a spit in the winter here because it won't burn.
I've run 55-1 in weather below 25* with zero adverse affects, same oil.
Same goes for the boat outboard motors. They are very temp sensitive compared to air cooled tools.
Tuning fat on the mill is a GIANT waste of power, fuel and oil, period imho.

Fuggin oil threads suck!View attachment 1029590

Yet here you are, coincidence, not.

16:1 was used when those old saws (like my PM270) ran on straight 30 or 40 weight motor oil mix (and somehow didn't immediately seize and burst into flames).
I run all my vintage saws 40:1 with Echo Power Blend and they love it.
Do not mix 16:1 with modern oil, you'll just kill mosquitoes.

But it tastes so good

When you actually start to spec the motor before the build, after break in and then again a good ways into your testing like maybe 2 or 300 hundred tanks later on the same oil mixed at a specific ratio on the same fuel, and that ain't easy, then you'll see a pattern of wear or not most don't.

25-1 certainly makes more power but you will taste it with a quality full synthetic brew.

One point to note that no one covers.
Detergents make or break an oil.
Thinner is better for mixed fuel. They did head in this direction for no reason. It's self explanatory if you understand fluid flow dynamics passing an orifice.
Extra oil not burned of the proper type will clean stuff you haven't even thought of yet.

Now remember I'm just some dumb piney over here who knows nothing. You'll want to ask an eggspert Plenty of them here and there with zero laboratory time in controlled tests so they really know what's up

Nuff said.