mixing ratios for 2 stroke chainsaws

[bwalker]

I might also say that I have operated motors with a high sample rate data logger and the exhaust temps and rpms continually bounce around.
It's impossible to draw any conclusions from this test or most home brew tests for that matter.

 

[ZeroJunk]

Manufacturers drop lemons all the time.
And that's not what you said... just admit they didn't tell you that in Stihl school..

Well, quote what I said. Should be simple.

Never been to a Stihl school.

 

[ZeroJunk]

Here, I'll do it for you.

Traditional two strokes always have. That’s the idea behind strato technology is to purge the exhaust with plain air rather than mixed fuel.

The 20-30% less comes from the strato air ports. The point being, if a motor is 30% more efficient due to the strato ports, that same fresh air that purges out the exhaust never went through the bottom end and lubricated the bearings

That makes sense. Still, to prove if 50 to1, 40 to 1, 32 to 1, or whatever makes a difference you have to test it against another test group. Otherwise, you are just believing something .
Stihl says you can run the HP Ultra 70 to 1 with no problems. And, you can bet they have tested it.
Hell, Amsoil says 100 to 1 .
In the meantime I have a Lawn Boy 2 stroke that says 32 to 1 right on the cap and I have been running it 50 to 1 for 30 years. I have had to replace the gear box, the rear wheels several times, front wheels several times. The deck is welded up like Frankenstein's face. And, it just keeps going.
I take all of the clutter with a lot of salt.

 

[ZeroJunk]

https://www.sciencedirect.com/topics/engineering/oil-film-thickness
Here is something to read. I suspect you could use it to prove or disprove what you already believe.

But, just look at the math calculations. There is a method to the madness.

 

[camel2019]

50 to 1 and higher ratios are for the EPA. I will stick to my Dino oil and 32 to 1 since most of my saws were built before the summer of love I think that’s is a good idea.

 

[bwalker]

https://www.sciencedirect.com/topics/engineering/oil-film-thickness
Here is something to read. I suspect you could use it to prove or disprove what you already believe.

But, just look at the math calculations. There is a method to the madness.

https://www.sciencedirect.com/topics/engineering/oil-film-thickness
Here is something to read. I suspect you could use it to prove or disprove what you already believe.

But, just look at the math calculations. There is a method to the madness.

Not applicable to a two stroke.

 

[bwalker]

More like they are blowing 20% less raw fuel out the exhaust.

How about this.

 

[bwalker]

50 to 1 and higher ratios are for the EPA. I will stick to my Dino oil and 32 to 1 since most of my saws were built before the summer of love I think that’s is a good idea.

That's not exactly true. The EPA doesn't regulate oil ratios. They do regulate unburnt HC, but oil has a min effect on that.
The MFG went to 50:1 before the EPA was very involved in regulating small engines. The reasoning was that they wanted to limit visible smoke with the relatively poor oils of the time and they wanted to limit plug fouling given that most people can't tune a carb to save their lives.
Never mind the fact that the engines themselves materials wise either didn't change at all or changed minimally.
Latter when strato engines started to appear on the market failures increased and this really can't be denied. Rotating assembly weight increased, oil through the engine decreased due to fuel efficiency improvements and heat increased due to less fuel cooling the motor and increasingly choked up mufflers.
In the racing world its been known for years that running more oil in your fuel leads to longer engine life and more power. In fact some of these.engines are so high string that they simply won't live at something like 50:1 and as a result they use thick ester oils or castor based oils at ratios around 16:1. These engines are Smokeless once warmed up snd internally they remain very clean as long as castor isn't used. I've been inside Yamaha KT100 air cooled kart motors that are perfect in regards to cleanliness when ran on Yamalube 2R at 16:1.
Like wise I have been inside saws and other O P E ran at 32:1 that look perfect.

 

[huskihl]

Here, I'll do it for you.


That makes sense. Still, to prove if 50 to1, 40 to 1, 32 to 1, or whatever makes a difference you have to test it against another test group. Otherwise, you are just believing something .
Stihl says you can run the HP Ultra 70 to 1 with no problems. And, you can bet they have tested it.
Hell, Amsoil says 100 to 1 .
In the meantime I have a Lawn Boy 2 stroke that says 32 to 1 right on the cap and I have been running it 50 to 1 for 30 years. I have had to replace the gear box, the rear wheels several times, front wheels several times. The deck is welded up like Frankenstein's face. And, it just keeps going.
I take all of the clutter with a lot of salt.

I’ve been messing with the insides of saws for about 10 years. Seen many tree service strato saws within a year or 2 of being new with bad crank bearings. Once the owners were advised of better oil and using more of it, the problems went away. I know of several 5 series huskies with 300-500 hours with bad bearings. I also know of several that have 1500 hours on the original bearings. The difference? Low quality oil at 50:1 vs high quality oil at 32 or 40:1. Hours verified with the CST.

The issues are there if you seek them out

 

[ZeroJunk]

How about this.

Exactly.

 

[The Shooters Apprentice]

 

[bwalker]

Exactly.

You didn't have a clue or you wouldn't have made that comment.

 

[ZeroJunk]

I’ve been messing with the insides of saws for about 10 years. Seen many tree service strato saws within a year or 2 of being new with bad crank bearings. Once the owners were advised of better oil and using more of it, the problems went away. I know of several 5 series huskies with 300-500 hours with bad bearings. I also know of several that have 1500 hours on the original bearings. The difference? Low quality oil at 50:1 vs high quality oil at 32 or 40:1. Hours verified with the CST.

The issues are there if you seek them out

I don't doubt you. There were complaints with larger displacement Husqvarnas going back at least a decade that I am pretty sure were single intake. And, guys were saying that 32 to 1 helped.

I still have some questions. Of that percentage of oil wasted out the exhaust, how much could have been stacked on bearings anyway? I don't know. How much oil can be attached to the surface of a bearing ? I don't know. At some point it is like pouring water on the hood of your car./

I was told that the reason why older saws had a heavier mix in addition to the oil not being as good was that the tolerances were sloppier. I don't know.

My thinking is simply that the engineers who blend the oil and design the saws do.

But, it would be foolish to think nothing slips through the cracks as well.

I have one tree service customer that has three of the non Mtronic 362's that have that dual intake carb. He works them hard. Only problem he has had is his men manage to get that stupid piece of linkage out of the slot somehow. You couldn't do it trying. And, I took some 1708 fiberglass and epoxy and repaired a broken rear handle, Probably 5 years ago and still holding fine. I have no idea what oil he runs, but he just gets regular ethanol at the gas station every day. Hell, he's still using an 044 that has who knows how many hours on it. Think I replaced the carb, fuel line, and tank vent once.

Anyhow, I work on a lot of MS201T's for some reason. Big saws are rare. I rebuilt a MS462C that hung a skirt a few weeks ago. But, mostly home owner saws. And, blowers, weedeaters, trimmers, and pole saws forever.

If there is a logger in the bunch I don't know them.

 

[ZeroJunk]

You didn't have a clue or you wouldn't have made that comment.

You do realize that the theory behind "strato-porting" is so you don't waste raw fuel out the exhaust don't you ?

 

[Bob Hedgecutter]

You do realize that the theory behind "strato-porting" is so you don't waste raw fuel out the exhaust don't you ?

I believe Kevin mentioned that way back in post #101 of this thread- keep up with the play!

 

[ZeroJunk]

I’ve been messing with the insides of saws for about 10 years. Seen many tree service strato saws within a year or 2 of being new with bad crank bearings. Once the owners were advised of better oil and using more of it, the problems went away. I know of several 5 series huskies with 300-500 hours with bad bearings. I also know of several that have 1500 hours on the original bearings. The difference? Low quality oil at 50:1 vs high quality oil at 32 or 40:1. Hours verified with the CST.

The issues are there if you seek them out

Oh, I did put a piston in a MS500I after one tank using a 36 inch bar. Veteran tree service guy.
Started to post in the 500I thread put figured I would get in to another circular logic battle with another moron.

 

[bwalker]

I don't doubt you. There were complaints with larger displacement Husqvarnas going back at least a decade that I am pretty sure were single intake. And, guys were saying that 32 to 1 helped.

I still have some questions. Of that percentage of oil wasted out the exhaust, how much could have been stacked on bearings anyway? I don't know. How much oil can be attached to the surface of a bearing ? I don't know. At some point it is like pouring water on the hood of your car./

I was told that the reason why older saws had a heavier mix in addition to the oil not being as good was that the tolerances were sloppier. I don't know.

My thinking is simply that the engineers who blend the oil and design the saws do.

But, it would be foolish to think nothing slips through the cracks as well.

I have one tree service customer that has three of the non Mtronic 362's that have that dual intake carb. He works them hard. Only problem he has had is his men manage to get that stupid piece of linkage out of the slot somehow. You couldn't do it trying. And, I took some 1708 fiberglass and epoxy and repaired a broken rear handle, Probably 5 years ago and still holding fine. I have no idea what oil he runs, but he just gets regular ethanol at the gas station every day. Hell, he's still using an 044 that has who knows how many hours on it. Think I replaced the carb, fuel line, and tank vent once.

Anyhow, I work on a lot of MS201T's for some reason. Big saws are rare. I rebuilt a MS462C that hung a skirt a few weeks ago. But, mostly home owner saws. And, blowers, weedeaters, trimmers, and pole saws forever.

If there is a logger in the bunch I don't know them.

What your really asking is about migration time. Google up "two cycle oil migration time".

 

[bwalker]

You do realize that the theory behind "strato-porting" is so you don't waste raw fuel out the exhaust don't you ?

Of course I do... but it also leads to less oil moving through the motor. You do understand that now, right?

 

[fastduc]

Running more oil will displace a small amount of fuel. 3 ingredients are pushed into your engine by atmospheric pressure, air, fuel and oil. If you put more oil in the mix you will displace air causing a leaner condition in the combustion chamber. So many variables (Jet size, oil type barometric pressure temperature of the saw, octane of the fuel all play into the factoring of the optimal fuel oil ratio). From my experience it is best to use qualty oil mixed at the ratio determined by the factory engineers. FWIW

 

[camel2019]

Running more oil will displace a small amount of fuel. 3 ingredients are pushed into your engine by atmospheric pressure, air, fuel and oil. If you put more oil in the mix you will displace air causing a leaner condition in the combustion chamber. So many variables (Jet size, oil type barometric pressure temperature of the saw, octane of the fuel all play into the factoring of the optimal fuel oil ratio). From my experience it is best to use qualty oil mixed at the ratio determined by the factory engineers. FWIW

Or just turn the screws and run more oil