2 stroke equipment mix ratio

[Cujet]

Engines with reed valves, single piston rings, and/or very high RPM (think 14,000 Husky chainsaws) will likely benefit from the additional oil of a 32 to 1 mix. Also, while there are claims that "today's" oils are markedly better than in the past, that may not be quite as "so" as people claim. 2t oils started out as straight 30, then Bright Stock, but today the base stock is now very likely to be a Polybutene for low smoke reasons. All of which have somewhat similar film strength. (castor oil being the exception)

The bottom line remains the same, the oil ratio you choose has a direct relationship on the amount of lubrication your engine receives. As does the RPM, with higher RPM needing more oil, due to internal oil migration issues. Put another way, high RPM simply blows the oil out, rather than having it accumulate (yes the oil does accumulate and visibly migrate) on the crank bearings, connecting rod and cylinder walls.

 

[Mike72]

Engines with reed valves, single piston rings, and/or very high RPM (think 14,000 Husky chainsaws) will likely benefit from the additional oil of a 32 to 1 mix. Also, while there are claims that "today's" oils are markedly better than in the past, that may not be quite as "so" as people claim. 2t oils started out as straight 30, then Bright Stock, but today the base stock is now very likely to be a Polybutene for low smoke reasons. All of which have somewhat similar film strength. (castor oil being the exception)

The bottom line remains the same, the oil ratio you choose has a direct relationship on the amount of lubrication your engine receives. As does the RPM, with higher RPM needing more oil, due to internal oil migration issues. Put another way, high RPM simply blows the oil out, rather than having it accumulate (yes the oil does accumulate and visibly migrate) on the crank bearings, connecting rod and cylinder walls.

All two cycle oils lubricate, from the old two cycle oils of 50 years ago up to today's two cycle oils and even the once used straight 30. Does any one of them lubricate better than the others? I think it would be hard to determine. There are other real reasons why today's two cycle oils are markedly better. The obvious one being they smoke less, a lot less. Another is the amount and type of carbon they leave behind. The old two cycle oils and straight 30 both left a hard type of carbon deposit that eventually seized rings and scored pistons. Also using these oils caused blocked exhaust ports, and fouled spark plugs in a fairly short amount of hours. By contrast, today's two cycle oils produce a soft carbon that does not damage the engine and allows for greatly extended port cleaning and spark plug life. For anyone who puts a lot of hours on their equipment these new oils are a big improvement. I agree the higher rpm engines need more oil in the mix, but the majority of two cycle engines in use today need only a 50:1 mix ratio.

 

[JimmyChainsaw]

All two cycle oils lubricate, from the old two cycle oils of 50 years ago up to today's two cycle oils and even the once used straight 30. Does any one of them lubricate better than the others? I think it would be hard to determine. There are other real reasons why today's two cycle oils are markedly better. The obvious one being they smoke less, a lot less. Another is the amount and type of carbon they leave behind. The old two cycle oils and straight 30 both left a hard type of carbon deposit that eventually seized rings and scored pistons. Also using these oils caused blocked exhaust ports, and fouled spark plugs in a fairly short amount of hours. By contrast, today's two cycle oils produce a soft carbon that does not damage the engine and allows for greatly extended port cleaning and spark plug life. For anyone who puts a lot of hours on their equipment these new oils are a big improvement. I agree the higher rpm engines need more oil in the mix, but the majority of two cycle engines in use today need only a 50:1 mix ratio.

Mike,you have summed it up very well.Thankyou.

 

[64bawagon]

I have several pieces of stihl lawn equipment and none of them like a heavy oil dose. They run best at 50:1 and get boggy if I add more. Mostly I just pinch my sons crazy expensive motorcycle 2 stroke oil

 

[spasm3]

I have several pieces of stihl lawn equipment and none of them like a heavy oil dose. They run best at 50:1 and get boggy if I add more. Mostly I just pinch my sons crazy expensive motorcycle 2 stroke oil

If you change the ratio a good bit, you have to retune the carb.

 

[64bawagon]

If you change the ratio a good bit, you have to retune the carb.

Seems as soon as I hit the sweet spot the weather changes.

 

[ARCOgraphite]

Europe allows 2 stoke machines !!?

 

[FZ1]

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.

Get a mixing bottle to mix the various blends. Use a good 2 stroke oil and the oem spec for ratio. I like echo products for easy starting. Jmo

 

[oilcandave]

On a jeweled bearing motor piston skirt to cylinder is where problems are most likely. If piston thrust is towards the intake side less issues. If towards the exhaust side things are hotter and dryer...more oil is helpful...

I jet to and run 32/1 on all my stuff. 50/1 was a boardroom decision.

 

[jake wells]

Boardroom decision or not i run 50:1 to not have two separate cans laying around been running it for years without problems and will continue to do so.

 

[billt460]

I wouldn't run ANYTHING on 50:1. Or would I use 10% Ethanol gas. I mostly run 32:1, except for my Homelite chain saw that uses 16:1, and my Chi-Com saw "Salem Master" that uses 25:1. (I run 16:1 in that as well). All mixed with 93 Octane non Ethanol fuel.

 

[wpod]

I am from a different continent.....but thanks to BITOG I know that some 2stroke equipement over the pond has TCW-3 oils in their manuals....

Dunno why exactly...if it is aircooled engine....I would run FC/FD oils in it anyway (over the TCW-3 spec)

High RPM engines vs low RPM engines.