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

[jeff9366]

I have one 2-cycle engine, a Stihl MS-261 chainsaw, the smallest saw in Stihl's professional grade offering.

Per instruction, I use (Chevron) 87-octane mid-premium gasoline in this saw. Gasoline contains 10% ethanol in Florida.

Until yesterday I have used Supertech (standard) 2-cycle engine oil, mixed 50:1. Cost $1.64 for 6.4 ounces.

One gallon of chainsaw mix lasts me three weeks.

Yesterday purchased Supertech FULL SYNTHETIC 2-cycle engine oil. Cost $2.64 for 6.4 ounces.

Should I maintain 50:1 gasoline : oil ratio?
Generic directions on Supertech container say: "Always follow manufacture's recommended mix ratios for optimum performance and protection." Stihl offers no guidance for FULL SYNTHETIC oil in 2012 edition of MS-261 Owner's Manual.

I buy chainsaw gasoline one gallon at a time. 50:1 ratio is 2.5 ounces of 2-cyle oil per gallon of gas, so a 6.2 ounce container mixes 2-1/2 gallons of chainsaw gas.

Will I notice a performance or longevity improvement for my extra $1.00 per container of FULL SYNTHETIC 2-cycle engine oil?

Other considerations?

I operate in Florida. No cold temperatures.

 

[ericm979]

Re: FULL SYNTHETIC 2-cycke engine oil in Stihl MS-261 chainsaw?

I've used synthetic oil in all my two stroke motorcycles (street, road race, off road) and equipment like chain saws for 30 years. I've had zero problems due to oil failure. Every engine I've torn down has looked good- it's always been something else that broke, not an oil related problem. Two strokes are highly stressed and the small amount of oil gets worked hard. Synthetic is more stable than dinosaur oil under high temperatures.

Use the same ratio. Basically you should use as much oil as you can while maintaining good running characteristics. I used 32:1 or more oil for road racing and general off road riding. For observed trials which stresses the engine less but requires there be no loading up ever, 50:1 for air cooled and 70:1 for water cooled bikes. I run my saws and other two stroke equipment at the manufacturer recommended 50:1.

I'm still working through my last gallon of the Redline synthetic I ran in my trials bikes. Oil is cheaper in bulk than in the small bottles. I use a ratio-rite to measure out the oil and rinse it out with gas then pour that into the can to get all the oil I measured into the gas. There'll be no performance difference. Some synthetics make the exhaust smell better than regular oil, some make it smell worse. I stopped using Motul in my trials bikes because other competitors complained about the smell.

 

[jeff9366]

ERICM: Thank you. I speculated MS-261 idle might increase radically with full synthetic oil/gas mix. Reassuring.

 

[SSdoxie]

Majority of my 2 cycle fuel use is with the boat, pre-mixed @ 50:1, no oil injection. I use Mercury Quicksilver full synthetic and use this same in chainsaws, weed eater, and leave blower. I try to keep a gallon mixed @ 40:1 on hand as the chainsaws and other tools vary from 32 - 50:1 ratio. Many times over the years I have run out in middle of a job and gas out of the boat using that without adding any extra oil and had no problems to date. I have access to non-ethanol and use it most of the time but keep a bottle of marine ethanol on had to use when I don't pay the extra $ for non-ethanol.

 

[Ford850]

I've used the Stihl HP Ultra full synthetic oil for years. I think it is cleaner burning, especially noticeable in my blower. I used to mix with 89-octane, but have recently found a station selling 90-octane which is ethanol free.

 

[jeff9366]

I've used the Stihl HP Ultra full synthetic oil for years. I think it is cleaner burning, especially noticeable in my blower. I used to mix with 89-octane, but have recently found a station selling 90-octane which is ethanol free.

Does Stihl recommend you mix the Stihl HP Ultra full synthetic oil 50 : 1 ?

 

[Ford850]

Yes, their regular and synthetic oils are both mixed 50:1.

How To Mix Oil & Gas Guide | 5 to 1 Gas Oil Ratio Mixture Chart | STIHL USA

 

[Bird]

Does Stihl recommend you mix the Stihl HP Ultra full synthetic oil 50 : 1 ?

And that's what I'm using in my Mantis tiller.

 

[Clay45]

Majority of my 2 cycle fuel use is with the boat, pre-mixed @ 50:1, no oil injection. I use Mercury Quicksilver full synthetic and use this same in chainsaws, weed eater, and leave blower. I try to keep a gallon mixed @ 40:1 on hand as the chainsaws and other tools vary from 32 - 50:1 ratio. Many times over the years I have run out in middle of a job and gas out of the boat using that without adding any extra oil and had no problems to date. I have access to non-ethanol and use it most of the time but keep a bottle of marine ethanol on had to use when I don't pay the extra $ for non-ethanol.

I did the same thing because when it first came out that was the first "ashless oil". But later formulations were made for two-cycle Air cool engines (TCA} and two-cycle water cooled TCW engines.

 

[jeff9366]

Yes, their regular and synthetic oils are both mixed 50:1.

How To Mix Oil & Gas Guide | 5 to 1 Gas Oil Ratio Mixture Chart | STIHL USA

Thank you.