Stihl 4-Mix Oil?

[bwalker]

It’s already paid for itself , a few times over still going strong as when I bought it.

Hope it continues for you.

 

[WI_Hedgehog]

I think what I wrote is quite clear. Marine oils are ashless oils, Ultra is an ashless oil. Stihl formulated Uktra like they did for the same reason marine oils are formulated like they are. To reduce ash buildup.
In addition FB oils are not all ashless. The low ash FB oils are better for a air cooled two stroke, but obviously not as good as FC or FD. FC and FD can not be met with ashless oils.
So no, FC or FD oils can not always be used in place of FB oils.

STIHL Ultra isn't marine oil, it's outdoor power equipment oil.

JASO says FD exceeds FC which exceeds FB for two cycle oil, so unless someone is using oil under a different rating system made for a different purpose (like 4-stroke oil), FD can be used in place of FC which can be used in place of FB. Maybe that's what you're getting at, don't use four stroke marine oil in a 4-mix engine.

I have a KM-131R which has an intake and exhaust valve like @SteveSr's FS-111, the STIHL dealer that serviced it says either orange or silver bottle STIHL engine oil work fine (noting full-throttle keeps the spark screen clean), and any other decent two-cycle engine oil will work. My 131 is in great shape, no valve wear, no abnormal piston wear, spark plug is great, etc. I just started using CITGO Mystik 2-Cycle Sea & Snow Synthetic Blend Engine Oil (JASO FD) and don't expect any issues. Am I overlooking something?

 

[bwalker]

STIHL Ultra isn't marine oil, it's outdoor power equipment oil.

JASO says FD exceeds FC which exceeds FB for two cycle oil, so unless someone is using oil under a different rating system made for a different purpose (like 4-stroke oil), FD can be used in place of FC which can be used in place of FB. Maybe that's what you're getting at, don't use four stroke marine oil in a 4-mix engine.

I have a KM-131R which has an intake and exhaust valve like @SteveSr's FS-111, the STIHL dealer that serviced it says either orange or silver bottle STIHL engine oil work fine (noting full-throttle keeps the spark screen clean), and any other decent two-cycle engine oil will work. My 131 is in great shape, no valve wear, no abnormal piston wear, spark plug is great, etc. I just started using CITGO Mystik 2-Cycle Sea & Snow Synthetic Blend Engine Oil (JASO FD) and don't expect any issues. Am I overlooking something?

It's formulated exactly like a marine oil. And no a FC or FD oil can't always be used in FB applications for the reasons Inpreviously mentioned.
Besides that no OEM recommends a FB quality level oil or an ashless oil besides Stihl.

 

[SteveSr]

It's formulated exactly like a marine oil. And no a FC or FD oil can't always be used in FB applications for the reasons Inpreviously mentioned.

Well, I understand the possible concerns about valve deposits however, It still doesn't explain why Stihl is recommending FC and FD oil for 4-mix applications in the E.U.

I am assuming that Stihl would have tested FC and FD oil in the 4-mix applications before recommending them. Where are the data points that shows actual issues with FC and FD oils in 4-mix engines?

 

[bwalker]

Well, I understand the possible concerns about valve deposits however, It still doesn't explain why Stihl is recommending FC and FD oil for 4-mix applications in the E.U.

I am assuming that Stihl would have tested FC and FD oil in the 4-mix applications before recommending them. Where are the data points that shows actual issues with FC and FD oils in 4-mix engines?

Saying FC and FD are exceptable and recommending them are two different things. A 4mix will run on FC and FD just fine for a period of time. However, sooner or latter you will have the valve issues that plague these machines.
Regardless of what Stihl saws it's been well.provedn that using ash bearing oils in a 4 mix leads to issues.

 

[Lionsfan]

Saying FC and FD are exceptable and recommending them are twondifferent things. A 4mix will run on FC and FD just fine for a period of time. However, sooner or latter you will have the valve issues that plague these machines.

I've run mine on Husqvarna oil and Sabre the last few years (Local Stihl dealer went under). I've always looked at the potential vale issues as a " We'll cross that bridge when we come to it" kinda" deal. If I feel like tearing it down and fixing it, I'm more than capable of doing so. If I feel like throwin' the bitch out I'm financially stable enough to do that as well.

 

[Lawless]

I got my KM91 from an estate, it looks like new. I ran Red Armor in it all summer and will continue. I plan to check it close for carbon this winter but the muffler shows no signs of trouble.

 

[WI_Hedgehog]

Well, I understand the possible concerns about valve deposits however, It still doesn't explain why Stihl is recommending FC and FD oil for 4-mix applications in the E.U.

I am assuming that Stihl would have tested FC and FD oil in the 4-mix applications before recommending them. Where are the data points that shows actual issues with FC and FD oils in 4-mix engines?

2-cycle JASO FD rated oil has less ash according to JASO Table 3, and in Table 2 less smoke and less exhaust screen blocking. The JASO document says FD is better than FC, FC than FB, and as far as I've understood the thread, if we're running 2-cycle oil in a 4-mix engine it's all good.

I can understand how all bets are off if running 4-cycle oil, marine specific oil, or olive oil, but as far as 2-cycle JASO rated oil goes the higher the letter the better.

Another thread on the topic, the summary is the same (FD is better), run the recommended 50:1 ratio, and don't bog the engine--run higher RPMs instead:
https://www.arboristsite.com/threads/stihl-4-mix-engine-oil.369344/

 

[bwalker]

2-cycle JASO FD rated oil has less ash according to JASO Table 3, and in Table 2 less smoke and less exhaust screen blocking. The JASO document says FD is better than FC, FC than FB, and as far as I've understood the thread, if we're running 2-cycle oil in a 4-mix engine it's all good.

I can understand how all bets are off if running 4-cycle oil, marine specific oil, or olive oil, but as far as 2-cycle JASO rated oil goes the higher the letter the better.

Another thread on the topic, the summary is the same (FD is better), run the recommended 50:1 ratio, and don't bog the engine--run higher RPMs instead:
https://www.arboristsite.com/threads/stihl-4-mix-engine-oil.369344/

Yes, FD is better than FC and FC is way better than FB. However, that only pertains to air cooled two strokes. A 4mix is not an air cooled two stroke. Piston temps are way cooler, they have poppet valves etc. An ashless Marine type oil is actually better than a Air cooled FC/FD type oil in these engines which is what Ultra is.
The problem is in a 4mix mettalic ash, which is used in all FC, FD and some, but not all FB oils builds up on the valves and valve seats and that causes them not to close all the way or completely. The valve tips then begin to get hammered as the followers take up the slop. Running issues and or loss of compression starts to happen, etc. The higher the ash content the worse this is. So in reality FD is better than FC in this regard, not as good as an ashless FB formula like Ultra or a TCW3 marine oil.
Running a trimmer with the line out at lower RPM, but full throttle would actually be beneficial as the load is higher and the engines runs hotter
This makes combustion more complete and will generate less deposits. But on the other hand prolonged constant throttle would make the ash deposit issues worse as throttle variability helps remove ash buildup. With a Blower you don't have this option as they run at the same load at full throttle all the time, which is based on the fan design.

 

[lone wolf]

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 ?

Go to the 4 minute mark.

 

[WI_Hedgehog]

Yes, FD is better than FC and FC is way better than FB. However, that only pertains to air cooled two strokes. A 4mix is not an air cooled two stroke. Piston temps are way cooler, they have poppet valves etc. An ashless Marine type oil is actually better than a Air cooled FC/FD type oil in these engines which is what Ultra is.
The problem is in a 4mix mettalic ash, which is used in all FC, FD and some, but not all FB oils builds up on the valves and valve seats and that causes them not to close all the way or completely. The valve tips then begin to get hammered as the followers take up the slop. Running issues and or loss of compression starts to happen, etc. The higher the ash content the worse this is. So in reality FD is better than FC in this regard, not as good as an ashless FB formula like Ultra or a TCW3 marine oil.
Running a trimmer with the line out at lower RPM, but full throttle would actually be beneficial as the load is higher and the engines runs hotter
This makes combustion more complete and will generate less deposits. But on the other hand prolonged constant throttle would make the ash deposit issues worse as throttle variability helps remove ash buildup. With a Blower you don't have this option as they run at the same load at full throttle all the time, which is based on the fan design.

That explains what I didn't understand, thank you.

 

[bwalker]

Go to the 4 minute mark.

Using a bronze bushing in place of a roller bearing in a motor lubricated like a two-stroke is stupidity. About the only thing you can do to prolong bronze bushing life is up the oil ratio, but this will make the valve issues worse in a 4mix four stroke.

 

[WI_Hedgehog]

That's only in some blowers, albeit the worst blowers to use a bushing in...

Seems the STIHL oil is actually pretty good after all... my 2014 RedMax blower still fires on the first pull...

 

[jellyroll]

Using a bronze bushing in place of a roller bearing in a motor lubricated like a two-stroke is stupidity. About the only thing you can do to prolong bronze bushing life is up the oil ratio, but this will make the valve issues worse in a 4mix four stroke.

My friend runs supertech outboard at 32:1 in his 4 mix stuff. Apparently no problems

 

[North by Northwest]

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 seriously doubt Red Armor would cause any serious issues with a 4mix engine !

 

[bwalker]

That's only in some blowers, albeit the worst blowers to use a bushing in...

Seems the STIHL oil is actually pretty good after all... my 2014 RedMax blower still fires on the first pull...

I have abused redmax blowers to the max and never had any issues at all.
I currently run a Husky 580 which is a Redmax thats maybe 8 years old and it's never missed a beat.

 

[Chris1044]

I have a BR600 from 2010 that has an hour meter reading approximately 500 hours this season.

I've used stihl silver bottle synthetic whatever it is called now on it since it was new, at 50:1. Used year round...mixed with 87 octane, 10-15% ethanol content.

As an engineer immersed in the industry, it ain't the oil and I doubt it's the ethanol. It's called quality cuts in the name of profit...bean counters and MBAs.

So, awesome discussion that's going the way of most oil threads, but not sure I jump on the "it's the oil, stupid!" train.

 

[SteveSr]

So the potential issue with FD oil in 4-mix applications is the metallic ash components that collect on the valves. So how is this different than the metallic lead deposits that formed on the valves of car engines in the era of leaded gas pre-70's?

 

[Lionsfan]

So the potential issue with FD oil in 4-mix applications is the metallic ash components that collect on the valves. So how is this different than the metallic lead deposits that formed on the valves of car engines in the era of leaded gas pre-70's?

Completely different thing.

 

[bwalker]

So the potential issue with FD oil in 4-mix applications is the metallic ash components that collect on the valves. So how is this different than the metallic lead deposits that formed on the valves of car engines in the era of leaded gas pre-70's?

Lead oxides are much softer and leaded fuel had bromide based lead scavengers to prevent the deposits from getting too bad.