Oil Fuel ratio - OEM vs Farmertec Kit

[Axotopia]

Just browsing on Huztl's website and noticed the assembled MS660 and 372 clones (G660 and G372) both indicate a fuel-oil ratio of 25:1. Leads me to wonder why the big difference between Stihl & Husqvarna calling for 50:1 and Huztl using AM parts calling for 25:1.
The Huztl saws are assembled from AM parts that are close replicas of OEM, but probably with slightly looser tolerance. My ignorant mind assumes less precision should require less lubrication, maybe I am wrong.
Unlike Stihl, which dictates the engine oil specifications to use on their saws, Huztl's customers also consist of less affluent folks in developing countries, and may use whatever oil is available, let alone an EPA-like regulations. Thus the reason for a 25:1 mix as a worse case.
Wonder what you think is the reason for 25:1, which seems excessive amount of oil, and could cause carbon built-up and fouling. Also, would a chainsaw made from AM parts survive running at 50:1 ratio? Help educate a CAD newbie on some of chainsaw basics. Thanks.

 

[Conquistador3]

You generally indicate a higher oil to fuel ratio when you are either not sure of what oil the end user will put in the premix or are not sure of whatever you assembled.
Seeing how much time and money people sink into these Huztl kits due to poor fitting/shoddily made parts I'd say the later.

And another thing. In EM's, where people make a livelihood with chainsaws, you will very rarely, if ever, see a Chinese chainsaws in the field. The Stihl 070/MS720 is probably the most common saw in the world, followed by older Echo/Shindaiwa such as the CS1200/1201 and the 488. Chinese firms have been salivating to get into this market but they still have a very long way to go.

 

[67L36Driver]

Stihl, Husqvarna, Echo etc. have to please the EPA, hence the 50:1 mix.

The rest of the world, not being burdened by such issue, can mix what works for them. [emoji108]

 

[blsnelling]

Because the Huztl parts are inferior to OEM, thus requiring additional protection.

 

[Thoroughbred]

I think the general wisdom seems to be 40:1 for FarmerTec stuff just as a little extra protection. 32:1 if milling since that’s a rougher environment for a saw.

 

[Ketchup]

Interesting. I agree that Farmertec needs to compensate for lack of precision. The pistons are especially bad.

I also agree that EPA regulations have changed mix ratios dramatically in the last 30 years. My Homelite Zip runs 12:1 SAE 30.

Especially in smaller carbs I notice major differences in tune based on mix ratios. In the past I have found Huztl carbs to be next to useless. I wonder if running a 25:1 ratio would improve their performance. I rarely run a AM carb, but next time one comes through I'll try it.

Has anyone been running 25:1 in a clone?

 

[Conquistador3]

Zenoah and Echo started recommending 50:1 premix before Euro emission regulations came in being. I have an old Echo multitool powerhead whose bulky owner's manual clearly states 50:1 premix when using "JASO-FB rated synthetic-based oil".

I've run 50:1 premix for over 20 years. I am yet to experience one of the alleged nefarious effects of following what's written in the manual, but I don't **** around with my tools, store them without fuel and instead of mixing large batches of premix I do it in 2-5 liters installments according to need.
The only problem is that since ethanol hit our shores carburetors seem to last a whole lot less before overhauls/replacement, but oil has nothing to do with it. Politics on the other side...

 

[Ketchup]

I like 50:1, though my friends give me a hard time. I wouldn't put in my Zip, but I run it in my modern stock saws. I find it easier to tune and the saws run a little faster.

Milling with 32:1 is kind of like working out in a gas chamber, but my Mill saw is ported so I run 40:1.

Would running a thicker mix help protect from ethanol damage? Doesn't seem like it. I think the main thing is sloppy tolerances want more lubrication. Still, if the carb is engineered for 25:1...

 

[NSEric]

I think all the Chinese made 2 strokes recommend 25-1.
They use sae30 oil for some reason in china not good premix, at 25-1 you can run crap oil without killing the saw.
I run 40-1 in my Chinese saws without issue. I either use left over dirt bike gas or mix up some saw only gas with stihl premix.

 

[rayjay257]

We started running 50:1 using Golden Spectro oil in about 1973 or so in dirt bikes. MX bikes make a lot more HP/CI than chainsaws do, even back then when they were air cooled.

Part B. Take a container and put 25 oz of gas in it. Take another small container say 3 oz capacity and put 1 oz of oil in it. Then just look at each one. Even at this super rich mixture there is not much oil in all that gas. It's really amazing how long they last on such little oil.

 

[HarleyT]

Pretty much a silly topic.....

 

[ammoaddict]

I pump .9 gallon non ethanol 90 octane gas and 1 small bottle of Stihl ultra and 2oz seafoam. I use it in all my 2 strokes, Chinese, Swedish or German.

Sent from my Moto G (4) using Tapatalk

 

[Charles Bale]

Same here, .9 to a small bottle, or I do 3oz/gal if I am using H1-R

Haha, Golden Spectro! Mixed my first batch in 75' love that stuff! Smelled great coming out of jap mx bikes! I think I did 42:1 back then too!

 

[Cliff R]

Not really a silly topic but it does get kicked around, thread starters "beat down" and considerable coverage with varying opinions, etc.

Even though I work on power equipment daily and own a lot of 2 stroke stuff I can't get my head wrapped around how it survives with the only lubrication being a little oil thinned out in a butt load of gasoline. With the piston coming to the top of the hole nearly 100 times a second you'd think the rings and/or bearings would seize right up.

Anyhow, dating clear back to the early 1970's when I first started cutting wood to heat my parents farm house, then a few years later my brothers and my own, I've ran 40 to 1 mix in the highest octane pump fuel available. I also keep all of my saws and other 2 stroke equipment in perfect tune, never allowing them to go lean or free-rev at no load without "four stroking" just a tad. We cut well over 100 cords a year between myself, my brother and our sons. It's usually a group effort, as all of us heat with outdoor boilers. We own/manage several hundred acres between the four of us, and with all the Ash trees that need to come down our work load has more than doubled in the last couple of years.

Have had ZERO issues in all these years and never once seized a piston or smeared any aluminum over the rings and lost compression on anything. Never had a bearing, crankshaft or even a crank seal failure either. My 480CD has been in service since around 1980 when purchased new, has at least a zillion hours on it, and still has the original fuel line and pick-up in the tank, and never had a carb kit put in it either. It gets a steady diet of 40 to 1 mix, ALWAYS Husqvarna's best or equivalent, and I er on the richer side of 40 to 1 rather than the latter. I other words the large bottle of mix for 2.5 gallons which would yield 50 to 1 gets no more than 2 gallons of gas added to it.

I keep the fuel fresh, never allowing it to get over 6 months old for any reason, and most of the time (we use a lot of it) it's only several weeks old before being used up.

I'll also add that without exception IF I'm going to take a piece of power equipment out of service for any long periods I'll get it fully warmed up, dump the tank and just as it stalls out pull the choke and suck all the fuel out of the carb as it dies out. This has proven to work with this new E-10 fuel and I have zero issues here.

With that said not a day goes by a customer doesn't carry something up here to the shop and throw it on the counter that's FULL of "apple jelly" in the tank and carb all plugged up from letting it sit for many months and even years with this new fuel in it. Yes, ethanol is not your friend in a vented wet-flow fuel system unless you take steps to keep it in suspension and fresh.......FWIW......Cliff

 

[Axotopia]

Just trying to summarize and understand from what I am reading ... in modern chainsaws with OEM or AM parts, it sound like consensus is 40:1 for general use and 32:1 for milling should run fine; add a bit of Seafoam for extra seasoning. 50:1 is more to keep the folks at EPA and EU happy.
With all the growing number of AM parts getting put on chainsaws on eBay and CL without disclosures, it's helpful for me to know the working parameters.
Thanks for the feedback.

 

[ammoaddict]

Just trying to summarize and understand from what I am reading ... in modern chainsaws with OEM or AM parts, it sound like consensus is 40:1 for general use and 32:1 for milling should run fine; add a bit of Seafoam for extra seasoning. 50:1 is more to keep the folks at EPA and EU happy.
With all the growing number of AM parts getting put on chainsaws on eBay and CL without disclosures, it's helpful for me to know the working parameters.
Thanks for the feedback.

I use my same 45:1 mix when milling with my Chinese kit 660. I just tune it a tad richer.

Sent from my Moto G (4) using Tapatalk

 

[Trickyputt]

Interesting. I agree that Farmertec needs to compensate for lack of precision. The pistons are especially bad.

I also agree that EPA regulations have changed mix ratios dramatically in the last 30 years. My Homelite Zip runs 12:1 SAE 30.

Especially in smaller carbs I notice major differences in tune based on mix ratios. In the past I have found Huztl carbs to be next to useless. I wonder if running a 25:1 ratio would improve their performance. I rarely run a AM carb, but next time one comes through I'll try it.

Has anyone been running 25:1 in a clone?

Yes. I bought the g666 in the devilish blue but have yet to run a full tank of fuel. Detonation imminent, but if it survives 4 or 5 tanks I will lean it up unless I see reason not to, running highly specialized stihl oil vs 30w makes a difference perhaps. I have not even measured the operation temps on the saw yet.

 

[Charles Bale]

Yup, 3oz/gal is perfect mix. motocross bikes, chainsaws, weed wackers.

 

[HarleyT]

Because the Huztl parts are inferior to OEM, thus requiring additional protection.

So how would more or less oil matter?

Inferior metalurgy? Incorrect size/machining? Additional protection?? Does more oil mean more heat? Less?
Oil "quality"?

Please explain..........

 

[ericm979]

50:1 is more to keep the folks at EPA and EU happy.

Just because a lot of guys on the internet say it does not make it true.

The manual for my 025, made before EPA regs on chainsaws, calls for 50:1 if you're using Stihl synthetic oil, 25:1 otherwise.
I think the difference in oil ratios is because modern synthetic oils are that much better than cheap 30wt dinosaur oil. There are benefits to running less oil as long as it's sufficient for lubrication- there's less carbon on the plug, head and piston, and exhaust system. There's less of a chance of gumming up a ring (which can lead to seizure). When I was competing in motorcycle observed trials I ran 75:1 in my water cooled modern bikes and 60:1 in the air cooled vintage bikes. Trials bikes put out more HP/cc than chain saws but they're not run WFO as much. Never had an oil related problem.

40:1 isn't going to hurt anything other than having to remove the carbon from inside the engine more often. But 50:1 with good oil is plenty and will carbon up the engine less. I would agree with adding a little more oil for milling but again you're going to be taking that engine apart to clean it sooner.