Fuel mixture query

[onetruth]

I've bought a second hand Echo CS2900.

 

The guy I've bought it off says he's been using 50:1, but the manual says "any mixture other than 25:1 can cause malfunction of the engine".

 

Should I stick with 50:1 (which the engine's used to) or go over to 25:1? I'll be using Stihl 2-stroke.

[Rob D]

I've bought a second hand Echo CS2900.

 

The guy I've bought it off says he's been using 50:1, but the manual says "any mixture other than 25:1 can cause malfunction of the engine".

 

Should I stick with 50:1 (which the engine's used to) or go over to 25:1? I'll be using Stihl 2-stroke.

 

 

 

The way I understand it is in 'the old days' a mineral 2 stroke oil was used and needed to be 25:1

 

These days synthetic 2 stroke oils mean only need 50:1.

 

So should be fine with 50:1 but maybe see what else people have to say.

[spudulike]

The way I understand it is in 'the old days' a mineral 2 stroke oil was used and needed to be 25:1

 

These days synthetic 2 stroke oils mean only need 50:1.

 

So should be fine with 50:1 but maybe see what else people have to say.

 

That is quite correct - when this machine was made, the oil was not as good as it is now and 25:1 was normal, the ratio mix is set by the oil manufacturer and not the machine so in short 50:1 if you are using decent quality oil or 40:1 mix for caution or for a lower grade oil.

[onetruth]

Cool, thanks for the info, guys.

[onetruth]

the ratio mix is set by the oil manufacturer and not the machine so in short 50:1 if you are using decent quality oil

 

That's got me thinking - I've got some cheapo brand power tools that recommend 25:1. Do they do that because they expect their users to use cheap oil too? If I'm using Stihl oil for everything, should I run everything at 50:1?

[Jamis]

I managed to seize my father's B and Q special (Ryobi) running it on my 50:1 Stihl fuel, had been working fine on his cheapo 25:1 oil mix. They replaced it under warranty, but he still went and got a 260 instead.

[spudulike]

On the front of the Stihl oil it says 50:1 - the ryobi may have had other issues so can't comment or judge on it - I always run a 40:1 mix and have never had issues.

 

There is a ot about oil mix on arboristsite.com and they reckon the mix is dictated by the oil not the equipment.

 

perhaps the 25:1 produced lots of carbon and the Stihl flushed it out and killed the thing:confused1: