2 stroke equipment mix ratio

alex_at

alex_at

Joined
May 31, 2016
Messages
232
Location
Vienna, Austria
I recently started to clean up my 10700 squarefeet property. I bought an additional 2 stroke weed eater, house brand from a local hardware store. Manual calls for 1:40, I ran the first tank 1:25 but I got some popping noise under load. I believe that is called "popcorning".

I do have 2 Stihl chainsaws, a MS170 and a MS180, both call for 1:50. I have a small bottle Stihl HP Ultra oil as well as a 5 liter jug of Stihl Motomix. (Alcylate fuel with 1:50 Stihl HP Ultra).

Now the question is: Do I run my chainsaws 1:50? On arboristsite.com I read that many professionals run 1:40 and get much more life out of their equipment, some even 1:32 or 1:25

First tank on my MS180 I ran 1:40, the MS170 still sits in the box. A disadvantage of the MS170 and MS180 is a fixed jet carb, only idle speed is adjustable.

So what do I do? Simply run Stihl Motomix straight? Mix additional Stihl HP Ultra an bring the mix to 1:45 or 1:40? Or do I create a leaned out environment and do more harm than good long term?

The weed eater will get regular gas with part synth. 1:40, done. Was cheap and if it breaks it breaks. I suspect the engine will be the last thing to go bad on that thing.


Thanks for your patience, these 2 Stihls and store brand weed eater are my first 2 stroke machines that I ever had.
 
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Originally Posted by alex_at
I recently started to clean up my 10700 squarefeet property. I bought an additional 2 stroke weed eater, house brand from a local hardware store. Manual calls for 1:40, I ran the first tank 1:25 but I got some popping noise under load. I believe that is called "popcorning".

I do have 2 Stihl chainsaws, a MS170 and a MS180, both call for 1:50. I have a small bottle Stihl HP Ultra oil as well as a 5 liter jug of Stihl Motomix. (Alcylate fuel with 1:50 Stihl HP Ultra).

Now the question is: Do I run my chainsaws 1:50? On arboristsite.com I read that many professionals run 1:40 and get much more life out of their equipment, some even 1:32 or 1:25

First tank on my MS180 I ran 1:40, the MS170 still sits in the box. A disadvantage of the MS170 and MS180 is a fixed jet carb, only idle speed is adjustable.

So what do I do? Simply run Stihl Motomix straight? Mix additional Stihl HP Ultra an bring the mix to 1:45 or 1:40? Or do I create a leaned out environment and do more harm than good long term?

The weed eater will get regular gas with part synth. 1:40, done. Was cheap and if it breaks it breaks. I suspect the engine will be the last thing to go bad on that thing.


Thanks for your patience, these 2 Stihls and store brand weed eater are my first 2 stroke machines that I ever had.



On such a small property, I doubt you will run into longevity issues with these motors. I'd just buy Motomix a similar product and I wouldn't mess with the ratios and just run whatever each device calls for.

For a quarter acre, I'm surprised you aren't using battery powered devices. On my one acre property, I can trim all 660 feet of fencing, around all my trees, and around the garage on one 2 amp hour battery in my Echo cordless trimmer.
 
Yes, as long as the engine fuel ratio (and carb quality) allows for a richer oil mix (doesn't bog down) the engine will last longer. The EPA won't like you, and you'll have to clean carbon off the exhaust port and out of the muffler, particularly the spark screen, more often.

I don't run anything leaner than 1:40 and only that lean with synthetic oil. 1:25 is too rich, you'll get little extra benefit compared to the burden of performance and cleaning. Granted, older equipment isn't set up to run fuel as lean so there's that. The more fuel it's putting through, the more oil too at any given ratio.
 
IveBeenRued, I did check battery powered equipment. My local shop didn't recommend me the battery saws as they don't have that much cutting power as the gas powered ones. My concern as well with the chain saws was the battery storage and longevity. I use them to clean up, sell one keep the other. Then the battery most likely will be sitting more than it will get used. My experience with that is that the battery will be dead next time I want to use it.

I did look at battery powered push mowers, mainly for noise emmissions, so I thought I could use them late afternoon. But most of them in the up to 500$ range had a recommendation for maximum half the size of the property, the cheaper ones a quarter size. Same with the weed eaters. That's why I went with gas powered equipment.

So, I will stick with Stihl Motomix ready to use gas for the chainsaws and the cheap weed eater I will use regular gas with 40:1 part synth oil, which I have plenty of laying around for Diesel lubrication.
 
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Quote
For a quarter acre, I'm surprised you aren't using battery powered devices. On my one acre property, I can trim all 660 feet of fencing, around all my trees, and around the garage on one 2 amp hour battery in my Echo cordless trimmer.


Okay but what did that trimmer cost and how many years have you gotten out of it?

Looking at cost versus lifespan (including replacement batteries for the cordless), it tends to cost over twice as much to get the same work done with cordless, and only in recent years with (more expensive) 40+ volt systems, have cordless had remotely close to same performance as gas.

Then again my property borders a (somewhat unkept) field, and I have multiple garden areas so I need something with some grunt, an 18V wouldn't cut it (pun intended) despite that being really handy if it could due to being able to use same batteries as my other 18V cordless tools.

I'll stick with gas for anything demanding and/or that I'll likely use more than 20 minutes at a time, like chainsaw, mower, edger, snow blower, and still for a while longer till battery cost:performance ratio improves, weed wacker.
 
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Stihl 261 362 250
Husqvarna XP576
Tanaka pro trimmer
Echo blower
Lawn boy mower
All get C9 VPracing fuel mixed with VPracing 2stroke oil 40:1 I would and do use that mix on anything and everything OPE related no mater equipment recommendations and have been for years.
 
so, if 40:1 gets the most recommendations so far - I would use 40:1 in my MS170, MS180 - but the high speed side of the carb is non adustable, would I still be in a safe, not too lean ratio?

And mix my Stihl Motomix with some extra Stihl HP Ultra?
 
I'm a newbie. I follow the owners manuals. All of them call for 1:50, so that's what I ran during break-in and what I'll continue to run. I mainly heeded the advice from those on arborist sites, who seem to agree that there's no benefit of running rich, but there is the risk of gumming things up.
 
Originally Posted by Kamele0N
40:1.....32:1 in stuff that revvs @12.500rpms++ (550xp 560xp)

That is what I did. For trail riding I used 40:1. For blasting up sand dunes in the desert I ran 32:1.

I understand that the oil in the fuel ratio effected the air/ fuel ratio but I never had to mess with jetting when changing oil ratios.
 
Originally Posted by gathermewool
I'm a newbie. I follow the owners manuals. All of them call for 1:50, so that's what I ran during break-in and what I'll continue to run. I mainly needed the advice from those on arborist sites, who seem to agree that there's no benefit of running rich, but there is the risk of gumming things up.


Pretty sure you have that backwards, most pros do not use as low as 1:50, especially not those who repair their own equipment which should tell you something.
 
Originally Posted by Dave9
Originally Posted by gathermewool
I'm a newbie. I follow the owners manuals. All of them call for 1:50, so that's what I ran during break-in and what I'll continue to run. I mainly needed the advice from those on arborist sites, who seem to agree that there's no benefit of running rich, but there is the risk of gumming things up.


Pretty sure you have that backwards, most pros do not use as low as 1:50, especially not those who repair their own equipment which should tell you something.


Like I said, all I have to go on is my manual and the etherwebs. I trusted the arborist site members and where ever else seemed legit when I researched this last year.

Do you know of any 1:50 failures in MODERN equipment (eg, last 15 years)? Seriously, not being sarcastic.
 
Not true I bet most are at 44:1 3oz per gallon or better many still run 32:1 in everything.
 
I am not sure if this applies today but in the 70's Cycle World ran a test of ratios on the 2 stroke bikes available then. Ran different ratios and then pulled them apart to check wear. The least wear was with 30:1 I have used that ratio ever since I saw the results. I use it in my chainsaws that recommend 16:1. I have had no failures. One old Poulan and Husqvarna Rancher 44 are so old I can't get parts for them but they both still run great.
 
Originally Posted by vwmaniaman
I am not sure if this applies today but in the 70's Cycle World ran a test of ratios on the 2 stroke bikes available then. Ran different ratios and then pulled them apart to check wear. The least wear was with 30:1 I have used that ratio ever since I saw the results. I use it in my chainsaws that recommend 16:1. I have had no failures. One old Poulan and Husqvarna Rancher 44 are so old I can't get parts for them but they both still run great.



Do you suppose oil technology has advanced any in the ensuing 50 years? I suggest it probably has, not to mention one test, one sample, not much of a conclusive test. Not saying it won't hold water in the long run back then, but it's highly suspect. Waaaayyyy too many variables.But I do admit it's interesting reading.

With good modern oils, I would run all my 2 cycle OPE at 50:1 assuming the carb can be adjusted to run on that ratio. I've owned a ton of stuff that was 40;1 and 50:1 at the same time and always used good oil, ie Stihl, Echo, etc and run them all at 50:1 and never had a single problem. I've also checked the exhaust ports on all of them and you could still see the machining marks on the pistons after many years of use. Most all equipment with 40:1 would handle 50:1 carb adjustments easily, it's only when you get an old Lombard chainsaw that was 16:1 that I'm guessin the carb wouldn't handle the adjustment range. The difference in oil between 50:1 and 40:1 is .6 oz (6/10 of an ounce), that's pretty close. Now I try to mix as accurately as possible, but there is a certain amount of slop in any mix method, the oil doesn't all pour out of the measuring vessel, some gets slopped on the sife of the gas can mouth, you know what I mean, so there is a certain amount of error in that too. One reason I've been using TruFuel lately. Expensive, but I NEVER have a starting problem, even if I leave one of my chainsaws set for three years!
 
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32:1 is all I've ever used. My Stihl 041 Farmboss is 45 yrs old. Probably too oily for the weed wackers. They don't smoke, but the exhausts drip oil. Fine with me
grin2.gif
 
Originally Posted by gathermewool

Like I said, all I have to go on is my manual and the etherwebs. I trusted the arborist site members and where ever else seemed legit when I researched this last year.

Do you know of any 1:50 failures in MODERN equipment (eg, last 15 years)? Seriously, not being sarcastic.


... and the etherwebs, are also where there are just as many old hands which won't run 1:50.

Yes I know of 1:50 failures. Most consumer grade 2 cycles made 10+ years ago have failed already unless they hardly saw any use, so it's not find one, it's find one that didn't. If you use a contractor grade tool (engine) in a consumer duty cycle, then it can take years longer to notice the difference, but then you are paying a premium for it.

Consider the issue. Engines ran fine on 1:32 and 1:40 then there is the belief that by virtue of modern lubricants working better, the ratio can be reduced, which is just cancelling out much of that benefit. They're trying to suggest the least amount of oil necessary to make the lifespan long enough to satisfy the warranty and consumer demand, not to make the equipment run as long as possible.

Modern engines are much pickier about fuel, running lean smoothly. This is a step backwards in order to pollute less. At least there is that good, achieved goal instead of some conspiracy theory that they just want the equipment to wear out sooner to sell more, but ultimately it is the consumer choosing whether they want it cleaner running or longer lasting bearings. A dirty exhaust port you can clean, and I suppose you can replace bearings too, so the main thing is to recognize the trade-offs.
 
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