Stihl Motomix

[Johno219]

Hi All

can I mix Stihl Motomix with my regular petrol two stroke mix 

thanks

[peatff]

Do you mean use it in a saw running on pump fuel ? I've never had problems doing it with Aspen2 and it's pretty much same.

[Stubby]

4 hours ago, Johno219 said:

Hi All

can I mix Stihl Motomix with my regular petrol two stroke mix 

thanks

The only thing that can happen ( but usually on older saws that have been run on pump fuel all their life ) is that the petrol slowly attacks the rubber components removing the coating that is on them to keep them supple but at the same time keeping them supple anyway because they are being attacked .   Alkylate fuels ( like Aspen , Motomix and the Husqvarna one ) do not attack the rubber . So, if you use a saw on alkylate fuel from the get go there wont be a problem If you switch to alkylate fuel on a saw that's been run on pump fuel for a long time it can show up the damage that the petrol has done . The rubber components turn brittle and disintegrate  .   Some people think its the alkylate fuel causing the problem but its just showing it up . This is rare but can happen .

[Muddy42]

On 16/06/2022 at 18:13, Stubby said:

The only thing that can happen ( but usually on older saws that have been run on pump fuel all their life ) is that the petrol slowly attacks the rubber components removing the coating that is on them to keep them supple but at the same time keeping them supple anyway because they are being attacked .   Alkylate fuels ( like Aspen , Motomix and the Husqvarna one ) do not attack the rubber . So, if you use a saw on alkylate fuel from the get go there wont be a problem If you switch to alkylate fuel on a saw that's been run on pump fuel for a long time it can show up the damage that the petrol has done . The rubber components turn brittle and disintegrate  .   Some people think its the alkylate fuel causing the problem but its just showing it up . This is rare but can happen .

 

The cynical side in me would say surely its quite hard to scientifically prove what and when has caused the fuel line damage in a 20 year old saw that has had hundreds or tanks through it, multiple owners and hours of work and abuse? Yes, you can prove that ethanol damages rubber now, but also rubber, gaskets and plastic can degrade over time, or the saw overheated or something else caused the damage. 

 

Anyway, personally I still think it is worth switching old saws to Alkaylate now. If your fuel system has damage or letting in air you should get that sorted anyway to avoid lean mix etc.  Luckily my two 20 year old saws seem OK having switched to Alkayalte.

[Stubby]

25 minutes ago, Muddy42 said:

 

 

 

Anyway, personally I still think it is worth switching old saws to Alkaylate now. If your fuel system has damage or letting in air you should get that sorted anyway to avoid lean mix etc.  Luckily my two 20 year old saws seem OK having switched to Alkayalte.

Which it what I have done  since the availability of alkylate fuel .  Just pointing out what can happen , not that it will . I certainly have not had a problem .  

[Muddy42]

7 minutes ago, Stubby said:

Which it what I have done  since the availability of alkylate fuel .  Just pointing out what can happen , not that it will . I certainly have not had a problem .  

Great, that's good to hear!