Stihl 4-Mix oil ratio's?

[Chainmale]

Does anyone know if there's a reason I shouldn't run 32:1 in my Stihl 4-mix Combi's?

 

[hacskaroly]

Does anyone know if there's a reason I shouldn't run 32:1 in my Stihl 4-mix Combi's?

It will mean more oil....I run 40:1 in my FS-91 which is a 4-matic with no issues.

 

[Brad Button]

32:1 is way too rich. Over time you will get a lot of caron [unburnt] oil in the piston/cyl. You are much better off using what the manufacturer recommends. 40:1 is fine, I run both 40:1 and 50:1, and I use VP and Aspen fuels. In both my Stihl and Echo equipment.

 

[hacskaroly]

I use VP and Aspen fuels.

I use Harvest King...bottled by VP.

 

[DND 9000]

Use 50:1 like it is recommended by Stihl. Using more oil will carbon up the valves and valve seats. The HP Ultra oil was developed for these engines.

 

[Czed]

Does anyone know if there's a reason I shouldn't run 32:1 in my Stihl 4-mix Combi's?

They will indeed carbon up severely I've seen several that has
My nephew bought one over 12 year's ago runs 50/1 still running fine no issues.

 

[Chainmale]

Yea, was wondering about valves and seats. Also 4 stroke running a bit cooler.
Am trying not to use 2 different cans of mix, so might just stick to 40:1 for the saw's and Combi's iny work van, and 32:1 for my firewood saws.

 

[pro94lt]

it will run just fine @50:1

 

[Catbuster]

They will last longer at 50:1 with a synthetic oil. HP Ultra was designed specifically for that application. Too much oil will cause carbon buildup on valves and valve seats.

 

[pbillyi69]

i run 32:1 in my br600 the first time i ran it with that oil it have too high of octane fuel and didnt like it at all. but that gas is all gone and it runs fine i just had to adjust the carb.....so far no issues but i havent looked for any either. i have just made sure to keep the valves adjusted. it really didnt like 32:1 with the av gas at all but seems not to care about the extra oil so far

 

[lilspenny]

With Stihl Ultra it will increase carbon. Not really necessary. If you are running gas station oil 40:1. Boat oil in a pinch , then consider 32:1. That's my opinion as a 20 year 4-mix owner who has tried various oils many times. 4-mix engines need good quality gas, so consider that. So where can you buy good quality gas? It can be hit and miss. If you don't burn much consider VP gas in a can. 4-mix engines are sensitive to bad fuel/oil.

 

[Lawless]

I am using 32:1 Red Armor in my KM91, third season.

So far so good. It’s an experiment. I believe Red Armor is so good it will not build carbon on the valves so at some point it will be obvious if it does or doesn’t.

 

[lilspenny]

I am using 32:1 Red Armor in my KM91, third season.

So far so good. It’s an experiment. I believe Red Armor is so good it will not build carbon on the valves so at some point it will be obvious if it does or doesn’t.

What about ash?

 

[Lawless]

What about ash?

I don’t believe it will be an issue. It’s an experiment.

Red Armor is different in my experience, from most every other oil.

If it carbons up eventually, I will post it here and on AS. Several folks are interested in the outcome. So far, I have never even adjusted the valves and the cam has shown no wear.

 

[lilspenny]

I don’t believe it will be an issue. It’s an experiment.

Red Armor is different in my experience, from most every other oil.

If it carbons up eventually, I will post it here and on AS. Several folks are interested in the outcome. So far, I have never even adjusted the valves and the cam has shown no wear.

I finally adjusted the valves on my fs100rx after 10 years of commercial use and an additional 10 years of residential use. They were very close to spec. Cam was good. Stihl 4-mix engines will run for decades on FB oil.

 

[lilspenny]

I finally adjusted the valves on my fs100rx after 10 years of commercial use and an additional 10 years of residential use. They were very close to spec. Cam was good. Stihl 4-mix engines will run for decades on FB oil.