Stihl 4-Mix Oil?

[SteveSr]

Sorry for another oil thread. There has been some recent discussion on this forum concerning the correct oil for Stihl 4-mix engines. The conventional thoughts are that Stihl Ultra (a JASO-FB oil, now an old formulation) was designed specifically to work in the 4-mix engines and that newer formulations JASO-FC,FD should not be used and could actually cause issues if used in 4-mix engines.

Our local trail club has both chainsaws and weedeaters in the tool stable and we provide fresh mixed fuel during regularly scheduled workdays. It is therefore advantageous if we only had to use one type of mix oil.

So I did some international travel via the internet to Stihl's German website and found and downloaded the most recent manual for the FS-111 (some translation required). I also visited Stihl's USA website and downloaded the same FS-111 Owner's Manual.

The German manual indicates that JASO-FB, FC, FD are recommended/acceptable oils. The USA manual recommends Stihl Ultra for compliance with EPA and CARB requirements. In other words, Stihl likely used Ultra when they did their EPA and CARB compliance testing. So it would appear that if an FD oil will work in the EU/Germany it should also work in the U.S.

 

[WI_Hedgehog]

As far as I'm aware 2-Stroke FD oils can be used in place of FB oils.

3.2 Basic Concept of the Performance Classification

The performance level of 2-cycle oils is classified into three grades, FB, FC and FD, according to the test results based on the above-mentioned four JASO 2-cycle oil test methods. These are defined as FB, FC, FD from lowest to highest performance. The FC grade is defined for low smoke 2-cycle oils superior to FB with regard to exhaust smoke and exhaust system blocking. FD grade is defined as improved version of FC in terms of detergency performance at high temperatures.​

 

[Squareground3691]

Been using Motul 800 Off-road T-2 for over a decade, for all my 2T applications including BR700 & 800 never any issues, but the key is using a non- ethanol fuel ,

 

[ZeroJunk]

Beats me. We routinely get a BR600 or BR700, like one a week, that is practically new and seized on the wrist pin.
We put new short blocks in and Stihl pays for it. Every time.
Tell me what that means cause I don't know.
Never on a FS90, or 91, or FT131, or BR800 .

Why ?

 

[SteveSr]

Beats me. We routinely get a BR600 or BR700, like one a week, that is practically new and seized on the wrist pin.
We put new short blocks in and Stihl pays for it. Every time.
Tell me what that means cause I don't know.
Never on a FS90, or 91, or FT131, or BR800 .

Why ?

Any idea what oil is being used on the failed blowers?

BTW, we have just had a FS110 die possibly from a failed wrist pin bearing. Another volunteer is working on it so I don't have the details other than the crank locks up part way through rotation. Valves don't appear to be stuck/bent. This one likely lived its somewhat sheltered life on Ultra.

 

[Squareground3691]

Beats me. We routinely get a BR600 or BR700, like one a week, that is practically new and seized on the wrist pin.
We put new short blocks in and Stihl pays for it. Every time.
Tell me what that means cause I don't know.
Never on a FS90, or 91, or FT131, or BR800 .

Why ?

My BR 700 been flawless for 6 years, it’s all about oil and fuel , I believe,

 

[ZeroJunk]

Any idea what oil is being used on the failed blowers?

BTW, we have just had a FS110 die possibly from a failed wrist pin bearing. Another volunteer is working on it so I don't have the details other than the crank locks up part way through rotation. Valves don't appear to be stuck/bent. This one likely lived its somewhat sheltered life on Ultra.

They have Ultra in them when we get them. So, I don't see any reason to believe they were straight gassed. I did for a while. Obviously Stihl doesn't either.
Now, I have gotten them where the valve stem was so coated that the valves wouldn't close with Opti Max, but that is a whole different issue.

 

[ZeroJunk]

My BR 700 been flawless for 6 years, it’s all about oil and fuel , I believe,

Yeah, I don't know what is better or worse. Running them every day, or a few days a year.
I think sometimes running them every day is better.

 

[Squareground3691]

Yeah, I don't know what is better or worse. Running them every day, or a few days a year.
I think sometimes running them every day is better.

I use mine weekly

 

[ballisticdoughnut]

I’ve been running the VP mix oil in several of my 2 stroke machines including a KM131 (4 Mix) since new with zero issues. I don’t run the “factory” mix oil in anything I own. Haven’t had a single problem and I have pulled cylinders for inspection after months/years of use.

 

[Squareground3691]

I’ve been running the VP mix oil in several of my 2 stroke machines including a KM131 (4 Mix) since new with zero issues. I don’t run the “factory” mix oil in anything I own. Haven’t had a single problem and I have pulled cylinders for inspection after months/years of use.

Yup , like I said really believe it’s about oil and fuel mixture that produces positive long term results

 

[SteveSr]

Now, I have gotten them where the valve stem was so coated that the valves wouldn't close with Opti Max, but that is a whole different issue.

What is Opti-Max?

 

[SteveSr]

What is Opti-Max?

I think I found it online... Boat oil for water cooled mercury engines. Has no JASO or other rating on the bottle.

 

[ZeroJunk]

What is Opti-Max?

Sorry. I think Opti-2 was what I was trying to remember.
Anyhow, I have gotten two free BR-700 from lawn care contractor addicted to it because the city uses it I think.

Just take a Dremel tool with a brush and clean the valves and valve stems and back like new for my time, which is pretty much worth nothing.

 

[cscltd]

Br600 and br700 are seizing on wrist pin because they are not warmed up before giving unit full throttle.-especially when new

 

[jellyroll]

Beats me. We routinely get a BR600 or BR700, like one a week, that is practically new and seized on the wrist pin.
We put new short blocks in and Stihl pays for it. Every time.
Tell me what that means cause I don't know.
Never on a FS90, or 91, or FT131, or BR800 .

Why ?

Seen non roller wrist pins used on the br600 and 700. The 4 mix string trimmers uses a bearing.

 

[bwalker]

Sorry for another oil thread. There has been some recent discussion on this forum concerning the correct oil for Stihl 4-mix engines. The conventional thoughts are that Stihl Ultra (a JASO-FB oil, now an old formulation) was designed specifically to work in the 4-mix engines and that newer formulations JASO-FC,FD should not be used and could actually cause issues if used in 4-mix engines.

Our local trail club has both chainsaws and weedeaters in the tool stable and we provide fresh mixed fuel during regularly scheduled workdays. It is therefore advantageous if we only had to use one type of mix oil.

So I did some international travel via the internet to Stihl's German website and found and downloaded the most recent manual for the FS-111 (some translation required). I also visited Stihl's USA website and downloaded the same FS-111 Owner's Manual.

The German manual indicates that JASO-FB, FC, FD are recommended/acceptable oils. The USA manual recommends Stihl Ultra for compliance with EPA and CARB requirements. In other words, Stihl likely used Ultra when they did their EPA and CARB compliance testing. So it would appear that if an FD oil will work in the EU/Germany it should also work in the U.S.

I can see how you would arrive at that conclusion. Unfortunately it's a false one.
Consider these three facts. #1 Ultra us the only ashless oil sold by a chainsaw OEM for use in their equipment. #2. FC oils use mettalic detergents which produce ash when combusted. FD oils also use mettalic detergents.#3 the problems associated with 4 mix engines is caused by mettalic ash build up on the valves.
Given the above it no stretch to figure out why Stihl produced marketed ashless oil. It was to band aid fix the problems with 4 mix engines.
Some other pertinent information is an ashless oil cannot pass the detergency tests associated with both the FC and FD tests. In addition ashless oils have a long track record of not working well in air cooled motors are those that by virtue of their higher BMP run hotter pistons temps. This was well known back in the early 90's.

 

[bwalker]

Yeah, I don't know what is better or worse. Running them every day, or a few days a year.
I think sometimes running them every day is better.

Running a 4 mix would open for long periods of time tends to make the valve issue worse. Most applications that run steady throttle for long periods of time use ashless oil. Examples would be piston engine air craft, outboard motors, lawn boy mowers etc. Ashless I
Oils don't have any detergents in them, because detergents are mettalic based. This isn't an issue in a 4mix which runs much power piston temps than a two cycle, but can be very problematic in a 2 stroke. There is abundant evidence of this all over online. Using ashless oils in a 4mix is beneficial because they don't lay down ash on the valves and seats, which is what causes alot of the 4mix issues.

 

[bwalker]

Been using Motul 800 Off-road T-2 for over a decade, for all my 2T applications including BR700 & 800 never any issues, but the key is using a non- ethanol fuel ,

Ethanol really has nothing to do with it. And 800T is probaly one of the poorest choices you could use in a 4mix. It's higher in ash content than a FC or FD oil. In addition to mettalic detergents it also uses mettalic zinc based anti wear additives, which are not ccommonly ound in most air cooled two cycle oils. In addition it has a high end point because it's designed for high tress motors. A low stress, low temp 4 stroke is not the best match for this oil.

 

[OM617YOTA]

So is the solution to not get a 4mix engine?

Get a legit 4 stroke, or a legit 2 stroke, but don't try and combine them?