Two Stroke Mix Ratios

[MolaKule]

Originally Posted by KneeGrinder

...I'm on the record, I've run atleast 1000 gallons of premix of AMSOIL at 100:1 in a yz490, and a watercooled, powervalve, cr250 that I raced on closed coarse tracks, never seized, and never any signs of abnormal wear that some are stating.

More than another 1000 gallons, closer to 2000 gallons of Golden Spectro at 50:1 in another cr250 race bike, no seize either, no signs of any abnormal wear. Golden Spectro is a blend meant for 50:1 and does not have any other solvents added like other 2 stroke oils do. There is a difference in 2 stroke oils!


In water-cooled power valve equipment I can see where a synthetic 2-cycle oil of a 100:1 mix could work. There has to be different formulations for different applications.

In small engine Outdoor Equipment, where the cooling fins might get obstructed with debris, such as sawdust or grass, and considering the cooling systems aren't all that great, 50:1 or 40:1 ratios might be more appropriate.

Some time ago I had an ancient Chain Saw that I purchased second handed, and due to its carbeuration set-up and it's piston-to-bore fit, it required an SAE SJ 30 grade oil and a 32:1 ratio or it wouldn't run. Until the engine got real hot, this puppy would smoke a mosquito fog.

My wife could always tell where in the woods I was from the smoke.

 

[KneeGrinder]

Originally Posted by MolaKule
Originally Posted by KneeGrinder

...I'm on the record, I've run atleast 1000 gallons of premix of AMSOIL at 100:1 in a yz490, and a watercooled, powervalve, cr250 that I raced on closed coarse tracks, never seized, and never any signs of abnormal wear that some are stating.

More than another 1000 gallons, closer to 2000 gallons of Golden Spectro at 50:1 in another cr250 race bike, no seize either, no signs of any abnormal wear. Golden Spectro is a blend meant for 50:1 and does not have any other solvents added like other 2 stroke oils do. There is a difference in 2 stroke oils!


In water-cooled power valve equipment I can see where a synthetic 2-cycle oil of a 100:1 mix could work. There has to be different formulations for different applications.

In small engine Outdoor Equipment, where the cooling fins might get obstructed with debris, such as sawdust or grass, and considering the cooling systems aren't all that great, 50:1 or 40:1 ratios might be more appropriate.

Some time ago I had an ancient Chain Saw that I purchased second handed, and due to its carbeuration set-up and it's piston-to-bore fit, it required an SAE SJ 30 grade oil and a 32:1 ratio or it wouldn't run. Until the engine got real hot, this puppy would smoke a mosquito fog.

My wife could always tell where in the woods I was from the smoke.

And also, as I had stated, I tune, so changing main jets will also cool down cylinder temps drastically. Proper tune, fuel to air ratio, oil to fuel, what type of oil, type of fuel/ race fuel often, and as you stated, what type of engine, its all a combination like a padlock. Maybe how fast you go makes a difference also! Better air flow thru radiator=

What am I doing in Lawn Mower and Small Engine? guess I just saw AMSOIL 100:1 and 2 stroke, I do run plenty of OPE, I still use Stihl silver bottle for my saws, and an old leftover 2 liter bottle of Golden Spectro for my weed wacker and leaf blower. Both at 50:1. Saws are tuned though. 76.5cc's They don't smoke much.

 

[jakewells]

Molakule If the saw has a adjustable carburetor tune the high speed mixture screw to where it 4 strokes out of the cut and cleans up in the wood that is the ideal tune.

 

[AnthemBassMan]

Originally Posted by jakewells
Molakule If the saw has a adjustable carburetor tune the high speed mixture screw to where it 4 strokes out of the cut and cleans up in the wood that is the ideal tune.


That's exactly how I have my Echo CS370 saw set up. I pulled the limiter caps off the carb and set it the way it should be, not the extra lean factory setting. Adjust the low speed screw for quick throttle response from idle, then tune the high speed screw until you get the burble at WOT. But with rev limiters, you gotta do this while cutting so you're not fooled by the limiter.

As for synthetic 2 stroke oil, I have an email directly from Amsoil stating that they recommend no leaner than a 50:1 mix ratio for my Lawn Boys using their Saber. Modern 2 stroke engines can use the 80:1 mix. I know people have run that and 100:1 for years without damaging their engines, but it still makes me uneasy to do it.

L8R,
Matt

 

[MolaKule]

As I said, this was an ancient 30 pound monster that specified a 32:1 oil mix right on the sticker.

No limiter caps on the carb. No amount of tinkering with the carbs adjustment screws yielded any cutting power or reduced smoking except for those close to the factory setting.

 

[BigShug681]

Maybe I misunderstood what was discussed I'm saying I've had absolutely no issues running Amsoil's saber oil at a 100:1 ratio in newer Stihl OPE my 50 year old saw, it's homelite XL 12 that specs 16:1 and would never run a 100:1 ratio

 

[Astro_Guy]

IIRC my first piece of 2-cycle OPE was a Lawn-Boy mower, purchased in 1985. A 32:1 ratio was state of the art then; I remember the dealer going out of his way to tell not to use a 16:1 ratio. Rolling forward in the 90's, I recall chain saws, leaf blowers and weed wackers also calling for 32:1. Pretty much all of that equipment started to fail sometime after 2010 [stop running, not seize or go boom] due to Ethanol in the gas.

All of my first generation 2-cycle OPE, save for the mower, got replaced with Stihl equipment calling for a 50:1 mix. Given my experience with Ethanol, meaning 5 failed machines in a very short time span, I've been using Ethanol free premix ever since. My modus operandi has been to alternate between 40:1 and 50:1 TruFuel every time I buy fuel. I cannot say as I notice any difference between the two. Perhaps I will start to pull and clean the plugs at each change in mix ratio just to see if there is any noticeable difference. Thanks for the tip.

 

[demarpaint]

My OPE gets a 32:1 mix, with the exception of my outboard engine which calls for 100:1 mix, but was always run on 50:1. Many of the owners of engines from that ERA [mine is a 1988] ended up with blown motors running 100:. As a result the spec was changed back to 50:1. Fortunately I dodged that bullet.

 

[Mr_Joe]

I just mixed up another 1.5 gallons of mix fuel for the chainsaws & weed whipper. I mixed on the rich side of 50/1, so I think I'll call it good. It's non-ethanol fuel of course.

 

[Baveux]

OK , I bought my first 2 cycles trimmer a stihl fs40. Looks like a fuel/oil mix according to the manual is only good for 30 days or if you prefer should be used within 30 days.

I never had a 2 cycles engine before so bear with me , Am I going to screw up the oil and gas ratio of 50-1 if I add the recommended amount of stabil in my oil fuel mix ?

I know its not a lot of stabil in a tank but Im worry about not having enough oil in my gas after that addition of stabil ...

 

[AnthemBassMan]

Absolutely not. Add the Sta-Bil and rest easy.

L8R,
Matt

 

[Lawn_Care]

Originally Posted by Baveux
OK , I bought my first 2 cycles trimmer a stihl fs40. Looks like a fuel/oil mix according to the manual is only good for 30 days or if you prefer should be used within 30 days.

I never had a 2 cycles engine before so bear with me , Am I going to screw up the oil and gas ratio of 50-1 if I add the recommended amount of stabil in my oil fuel mix ?


While I run 40:1 in all my 2-strokes (trimmers, blowers, etc.), I've never had an issue over the winter.
Obviously mine never sits over 30-days without being used - except during the cold months.
I do use MMO per it's directions for my 2-strokes as well as the 4-stroke OPE I own.
Never had a problem the next spring. I only mix 1-gallon batches, so old gas is never really a problem for me.

For your use, i'd buy a can of the pre-mix from Lowes or any other big box store, put it in, and run it right before winter.
That stuff has a great shelf life and should not be a problem.
Adding a recommended dose of Sta-Bil will not hurt a thing either.

 

[andyd]

JASO FB TC W3 and TC WII meets or exceeds Valvoline Multi-purp 2 stroke 5.99 a qt at Auto Zone Says its ok for Lawn equip I mix a oily 32:1