Oil & Fuel FULL SYNTHETIC 2-cycle engine oil in Stihl MS-261 chainsaw?

[BrokeFarmerJohn]

I just looked up the MS-261, looks like a very capable saw, there looking very sleek now a days.

MS 261 Chainsaw | Professional Use Chainsaw | STIHL USA Mobile

One note is it does say, Note: STIHL recommends use of fuel with no more than 10% Ethanol content. Using fuel with greater than 10% Ethanol content may cause damage to your equipment and may void your STIHL warranty.

So I guess 10% is ok?

 

[BrokeFarmerJohn]

Probably new model numbers. Straight shaft is the way to go for sure. You really get a better product based on price unfortunately. That fs91 or any of its kin would be a good fit. I bought a 660 in 2013 or so. They are beasts for sure. I love firing it up around someone that has a small consumer grade saw and they are blown away at how deep it's idle is. Only run a 25" 3/8 chain on it. Chains stay sharp when you keep them out of the dirt. I can run a chain most of a day if I'm in pine, hardwood is a little harder on them. If I have a helper, they will go thru several chains. When they have to start paying for them they miraculously learn to run them right!

Brett

I have rode a quad and dirt bike that has less CC's than the 660 lol.

My main saw before the 660 was a MCculloch 1-53 80cc chainsaw with a welded tip bar, 24in bar with a .404 chain, manual oiler, it cut better over all than my Husqvarna 455 rancher. It was smelly, not balanced and felt like I was cutting wood with a anvil lol, still worth the effort. I still have that saw. 90% of what I cut was Oak, a few popular and cherry every now and then, only pine was hemlock which pops and crackles really bad, it's a poor wood for a fireplace.

I should restore the MCculloch

Mcculloch 1-53 - YouTube

 

[Silvic]

So I guess 10% is ok?

OK is a vague term but the Stihl reps say it is fine if you don't let it stand around very long. Any longer than two weeks is really pushing it.

 

[ericm979]

I have heard that you can't go back once you use synthetic oil in an engine. Would this hold true for a two stroke also?

No, and it's not been true for four stroke synthetic oil for about 30 years.

I ran my Stihl saws and weed eater on 87 octane for years without a problem. I'd mis-remembered the spec. Low octane causes detonation, which holes pistons or leaves small peck marks on the top of the piston. None of my equipment's got holed pistons or signs of detonation on the pistons. I think that the 89 octane spec gives a safety margin in case it's running lean (i.e. carb tuned at high ambient temps and then run at low temp without changing the tuning, or an intake leak). I've switched to 89 octane, its cheap insurance.

We can't get non ethanol gas here but it's all 10%. I find that there's no problems using gas that's 3 months old if it was treated with fuel stabilizer when I bought it and kept in a sealed container. I buy 5 gallons at a time and mix up 1 gallon at a time. The premixed fuel that the dealer touts is gas treated with fuel stabilizer and kept in a sealed container. I can do that myself.

I recently got an FS240 to complement the FS85. It's a beast. I did not want the FS130, it's their four stroke. I like two strokes.

 

[Texasmark]

I have heard that you can't go back once you use synthetic oil in an engine. Would this hold true for a two stroke also?

Hogwash. Stihl markets both types in the orange and silver containers and besides being a known fact......mixes easily with other oils and all, there are no warnings on the silver containers. Same smoke screen from claims that using ether addicts your machine to it......engine wear is what is addictive....the longer you run the engine the more wear it experiences meaning that if you needed ether initially, over time you will need more till you overhaul.

 

[jeff9366]

~~~~~DELETE

 

[SteveM70]

No, and it's not been true for four stroke synthetic oil for about 30 years.

I ran my Stihl saws and weed eater on 87 octane for years without a problem. I'd mis-remembered the spec. Low octane causes detonation, which holes pistons or leaves small peck marks on the top of the piston. None of my equipment's got holed pistons or signs of detonation on the pistons. I think that the 89 octane spec gives a safety margin in case it's running lean (i.e. carb tuned at high ambient temps and then run at low temp without changing the tuning, or an intake leak). I've switched to 89 octane, its cheap insurance.

We can't get non ethanol gas here but it's all 10%. I find that there's no problems using gas that's 3 months old if it was treated with fuel stabilizer when I bought it and kept in a sealed container. I buy 5 gallons at a time and mix up 1 gallon at a time. The premixed fuel that the dealer touts is gas treated with fuel stabilizer and kept in a sealed container. I can do that myself.

I recently got an FS240 to complement the FS85. It's a beast. I did not want the FS130, it's their four stroke. I like two strokes.

I guess I'm behind the times lol. I remember hearing that but once I decide on an oil for any engine that's what it lives on anyway.

I have three Stihl saws running on 87 octane. An 029, 362, and 660. I purchased the 029 new in 1998 and it's cut the majority of the wood to heat my home and my dads every winter since then plus the normal other jobs and is still going strong.

I use ethanol free gas in all my small engines now. I never had any trouble with the up to 10% ethanol stuff until last year. Maybe they upped the dosage in my area recently , I don't know but I'm done messing with it for small/carborated engines as long as I can get ethanol free.

 

[Wagtail]

I use a slightly heavier mix, around 45:1, can't remember if i bought synthetic last time, I found my saws ran better on the homelite oil than they did on the Stihl oil I had, I ended up mixing the two bottles together.

I always buy premium gas only because it takes a lot of cutting to burn even two gallons

I run my 2-stroke mix at no more than 45:1. The 'regular' petrol here is 91 octane with no ethanol.

I use the Stihl oil 'cause 2 litres came with my saw and I've had zero problems with it.

 

[TomSeller]

I use 91 octane ethanol free with the Stihl ultra synthetic and have never had a problem. I mix it using the little bottle for 2.5 gallons but usually slight the amount of gasoline I use to maybe 2.25 or 2.3 gallons or so. So I use slightly richer than 50:1

 

[spursjingles]

Use highest grade gas, 91 octane. You wont regret it. Its not $150 fillup. Its only 1 gallon.