Two Cycle Fuel Mixing ratios.

[Dr Dave]

The problem with ethanol is that it atracts moisture, and this can happen from the day it leaves the ehtanol plant.

Dave

 

[clemsonfor]

Stihl also recomends if you use anything but Stihl oil mix at 25:1, at least in my manual for my 8 yr old MS390. I use husky semi syn oil from Lowes mixed at 40:1 no problem so far. Use about 4 gallons a yr here recently.

 

[clemsonfor]

I use the Stihl Ultra 50:1, 89 octane gas (with ethanol), and the old red Stabil in both my 7.5 year old Stihl string trimmer and in my 5 year old Mantis tiller (bought reconditioned).

Stihl oil has a stabilizer already in it??

 

[Bird]

Stihl also recomends if you use anything but Stihl oil mix at 25:1, at least in my manual for my 8 yr old MS390. I use husky semi syn oil from Lowes mixed at 40:1 no problem so far. Use about 4 gallons a yr here recently.

I don't know if it's the age, or if that only applies to chainsaws, but my FS 55 Stihl string trimmer manual doesn't mention of mix ratios. It simply says to use Stihl 50:1 "or equivalent high quality oils". The string trimmer will be 8 years old in March.

 

[Bird]

Stihl oil has a stabilizer already in it??

It says so on the bottle, but I add StaBil anyway.

 

[3930dave]

Stihl oil has a stabilizer already in it??

Mine does. That is part of why Stihl will often extend the factory warranty (for free) at time of tool purchase, if you buy a six pack of their oil. You'd have to confirm with a long term Stihl dealer, but I suspect they've been supplying the oil with the stabilizer included for some time. Makes a lot of sense to do it that way.

Rgds, D.

 

[94BULLITT]

You have to buy the HP ultra which is full synthetic for them to double the warranty.

 

[clemsonfor]

the semi syn husky oil has stabilizer in it also.

 

[PandDLong]

Thanks for all the great info in this thread. I have been a slave to the original equipment recommendations and keep three different mixes on hand (a mini-tiller with a B&S at 24:1, a Jonsered chainsaw at 40:1, and a Stihl trimmer at 50:1). It's a real nuisance to keep fresh mixed fuel on hand for all 3 and I typically waste a bunch at the end of the season.

I look forward to the spring when I'm going to try out 50:1 for all of them (using the Stihl 50:1 oil).