Oil Fuel ratio - OEM vs Farmertec Kit

[Ketchup]

How does less oil help you you tune easier & the saw run faster?running lean will have more effect than oil ratio When the noted 2 Smoke guru's find the best result are the opposite .Sloppy tolerances are as such oil will neither do much to help but may have an adverse effect .Carbs aren't engineered for a particular oil fuel ratio they feed a mix amount through, the amount being regulated by the hole in the jet size saws tend to be tapered needle screwed in or out so increase/decrease the hole/size

I find thicker mix causes my saws to fourstroke more, requiring a leaner tune. Add elevation and my needles end up below 1/2 turn out on 32:1. I don't know why. My thought is there is more oil in the gas during combustion, causing a greater need for oxygen because there are more BTUs in the fuel. Maybe I'm way off.

I don't know what the chinese are thinking when they build carburetors. Maybe 25:1 is thick enough for carb needles to have more slop and still regulate close to shut. Fine tuning a huztl carb on 50:1 is an excercise in futility. But the chinese need chainsaws too, they must make them work somehow. Just wishful thinking there I suppose.

As far as Farmertec machining, its well documented they make pistons and cylinders with poor tolerances and obvious blemishes. More oil probably doesn't help or hurt. Well oiled junk is still junk.

 

[ken morgan]

Yee Haw another oil thread to F with the masses about....

 

[67L36Driver]

Yee Haw another oil thread to F with the masses about....

Yes, even I have fallen into their trap.

 

[NSEric]

If you want to get real technical checking to see if your using the right mix ratio you can pull the top end off the saw to check to see if the crank is oily and for a tiny puddle of oil sitting in the bottom end after running it for a while. If its dry you need more oil, ifs its oily your good to go
Guys have done this to 2 stroke bikes and found 50-1 isn't leaving much oil residue at all and 32-1 is leaving the crank oily, 40-1 is the happy medium and seams to be enough oil except for extreme use. The 25-1 the Chinese saws recommend is over kill to make up for using crappy oil.

 

[Charles Bale]

3oz/gallon (42:1)

 

[Trickyputt]

I am coming down on the side of 25:1 being the lowest common denominator given the at least 4 types of oil I know about. I saw an ad for a new amsoil 2 cycle oil stating up to 100:1 was ok.

 

[Axotopia]

Sorry to get some folks here all riled up. I think my initial dumb question as newbie is what is the basis for 25:1 for the Huztl AM chainsaws when OEM is 50:1.
My guess is unlike OEM parts which is based on engineered specs, the AM parts are look-alike that is almost to spec but most likely slightly off. So should someone who uses a AM parts modify their fuel-oil ratio closer to what Huztl indicates at 25:1, or stick with the OEM spec of 50:1?

Although my OEM saws had all been running running at 50:1 with no issues, I did put piece together a MS200T with 90% AM part that had gone through 20 odd tanks of gas at 32:1; exhaust port is very dirty and oily, internals looks clean and but very wet with oil, but intake boot recently melted ... guessing it is AM off-spec issues. Think I am going to test this AM saw at 50:1 after i repair the intake boot to see how far it goes before the saw fails.

 

[Trickyputt]

Sorry to get some folks here all riled up. I think my initial dumb question as newbie is what is the basis for 25:1 for the Huztl AM chainsaws when OEM is 50:1.
My guess is unlike OEM parts which is based on engineered specs, the AM parts are look-alike that is almost to spec but most likely slightly off. So should someone who uses a AM parts modify their fuel-oil ratio closer to what Huztl indicates at 25:1, or stick with the OEM spec of 50:1?

Although my OEM saws had all been running running at 50:1 with no issues, I did put piece together a MS200T with 90% AM part that had gone through 20 odd tanks of gas at 32:1; exhaust port is very dirty and oily, internals looks clean and but very wet with oil, but intake boot recently melted ... guessing it is AM off-spec issues. Think I am going to test this AM saw at 50:1 after i repair the intake boot to see how far it goes before the saw fails.

The short story from my point of view is that the ratio comes AFTER the choice of oil. The modern oils are highly expensive, highly engineered products that simply out perform older oil formulas. From what I have been checking out it may be erroneous to call them oils anymore. They are polymeric ester lubricant fluids at the high end and plant juice on the low end. Ratio is about the last thing to consider, since an oil type will come with a recommendation for its type and the oils are different. Nobody hardly talks about lubricity, and how it is an oil measurement standard, nor how it has been improved over the years in these new, modern oils.

 

[PP4218]

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]

This is correct per Stihl in one of their Patent Filings:

"BACKGROUND OF THE INVENTION
The invention relates to a motor chain saw that comprises an internal combustion engine for driving a saw chain circulating about a guide bar. The crankshaft of the internal combustion engine is oriented transversely to a longitudinal axis of the motor chain saw and supports at a first end a drive pinion for the saw chain as well as at the second end a blower wheel of a cooling air blower. The cooling air stream that is sucked in by the cooling air blower is supplied transversely to the longitudinal axis of the motor chain saw for cooling the cylinder of the internal combustion engine, flows about the cylinder positioned between the drive pinion and the cooling air blower, and then is blown out through a housing opening at the opposite longitudinal side. The motor chain saw further has a handle that extends across the motor housing transversely to the longitudinal axis and a hand guard that is arranged between the handle and the front end of the guide bar and is secured with at least one leg in the area of the housing opening for the cooling air.

Modern internal combustion engines, in particular single-cylinder internal combustion engines, are operated with a lean mixture for environmental reasons; this may cause an increased operating temperature. In order to ensure a satisfactory cooling action, a corresponding volume stream of cooling air must flow through the motor housing. On the other hand, increased operating temperatures also cause a corresponding heating of attached parts, for example, the exhaust gas muffler.

It is therefore an object of the present intention to not only sufficiently cool the internal combustion engine with a cooling air stream but also to supply cooling air to an exhaust gas muffler that is attached to the cylinder.

Source: https://patents.justia.com/patent/20100122674

 

[turbo15479]

The oil they use in China is not good so they need to run more oil. I have seven genuine Husqvarna saws, two Stihl saws, and six Chinese saws. My smallest saw is a 55 rancher which is really a homeowners saw but I bought this many years ago when I knew nothing. My other Huskies go from a 61 up through and including a 395xp. My two Stihl saws are an 044 and 036 pro. Chinese saws 272, 372xp, 372xpxt, 288xp, 395xp, and a 660. I run all my saws on good synthetic oil at a little richer than a 40 to 1 mix. I don't foul plugs and know I am running safe. For over a year I have been running the Chinese saws an average of 4 days per week and they are all still running strong. In fact I ported the Chinese 272, installed a pop up piston, and a dual port muffler and it runs well. I have not had the carb problems some people are having. My problems have been recoil on the 372xp broke, 272 would not oil enough until I made the slot in the plate between the saw and bar wider, and an oil pump on the 288. I just installed a genuine Husqvarna recoil on the 372xp. I bought all the saws on sale and paid less for all of them than I would have paid for one 395xp. In fact right now you can buy a Holzfforma orange 395xp with slow shipping for 269.10 delivered to your door. I repair my own saws so if something breaks it is not a problem. And if a top end wears out I will replace with a Meteor cylinder and piston.

 

[Timber MacFallen]

This is correct per Stihl in one of their Patent Filings:

"BACKGROUND OF THE INVENTION
The invention relates to a motor chain saw that comprises an internal combustion engine for driving a saw chain circulating about a guide bar. The crankshaft of the internal combustion engine is oriented transversely to a longitudinal axis of the motor chain saw and supports at a first end a drive pinion for the saw chain as well as at the second end a blower wheel of a cooling air blower. The cooling air stream that is sucked in by the cooling air blower is supplied transversely to the longitudinal axis of the motor chain saw for cooling the cylinder of the internal combustion engine, flows about the cylinder positioned between the drive pinion and the cooling air blower, and then is blown out through a housing opening at the opposite longitudinal side. The motor chain saw further has a handle that extends across the motor housing transversely to the longitudinal axis and a hand guard that is arranged between the handle and the front end of the guide bar and is secured with at least one leg in the area of the housing opening for the cooling air.

Modern internal combustion engines, in particular single-cylinder internal combustion engines, are operated with a lean mixture for environmental reasons; this may cause an increased operating temperature. In order to ensure a satisfactory cooling action, a corresponding volume stream of cooling air must flow through the motor housing. On the other hand, increased operating temperatures also cause a corresponding heating of attached parts, for example, the exhaust gas muffler.

It is therefore an object of the present intention to not only sufficiently cool the internal combustion engine with a cooling air stream but also to supply cooling air to an exhaust gas muffler that is attached to the cylinder.

Source: https://patents.justia.com/patent/20100122674

Lean mixture refers to the air/fuel ratio not the oil content within the mix.