Stihl "ONLY REGULAR GASOLINE MAY BE USED"

[7oaks]

Stihl just sent me a manual for the 090 (I've got the Contra and this was the closest manual they offered). On page 22 is the following warning:

"Only regular gasoline may be used. Never use high octane gasoline as it contains benzol which would permanently damage the carburetor diaphragms."

The copyright date on the manual is 1990 and it states: "Printed in West Germany".

In light of recent discussions on gasoline use, here, I thought someone might have insight as to whether this applies to all chainsaws and secondly if benzol is added to higher octane gasoline here in the States, today?

...Carl

 

[ckthorp]

Here is some info from the Wikipedia page on benzene:
"As a gasoline (petrol) additive, benzene increases the octane rating and reduces knocking. Consequently, gasoline often contained several percent benzene before the 1950s, when tetraethyl lead replaced it as the most widely-used antiknock additive. With the global phaseout of leaded gasoline, benzene has made a comeback as a gasoline additive in some nations. In the United States, concern over its negative health effects and the possibility of benzene entering the groundwater have led to stringent regulation of gasoline's benzene content, with limits typically around 1%.[15] European petrol specifications now contain the same 1% limit on benzene content. The US EPA has new regulations that will lower the benzene content in gasoline to 0.62% in 2011.[16]"

I would expect modern premium gasoline to be fine, but I'm curious to hear what the Stihl guys have to say about it.

 

[TreePointer]

Here's an excerpt from my new-this-year MS 290 owners manual:

Use mid-grade unleaded gasoline with a minimum octane rating of 89 (R+M/2). If the octane rating of the mid-grade gasoline in your area is lower, use premium unleaded fuel.

Fuel with a lower octane rating may increase engine temperatures. This, in turn, increases the risk of piston seizure and damage to the engine.

The chemical composition of the fuel is also important. Some fuel additives not only detrimentally affect elastomers (carburetor diaphragms, oil seals, fuel lines, etc.), but magnesium castings and catalytic converters as well. This could cause running problems or even damage the engine. For this reason STIHL recommends that you use only nationally recognized high-quality unleaded gasoline!
​

I assume "some fuel additives" would include these benzene compounds.

 

[ShoerFast]

Keep an extra carb-kit around just in case.

And run your Mid - higher grade gas.

 

[timberwolf]

I would think this was a warning that made sense at that time. When they banned lead they needed something to boost the octane of priemium gas, bezene aka benzanol did this quite well, but then they found out it also caused cancer so about 15-20 years ago banned or regulated how much of it could be in gas. It's a natural hydrocarbon component but with current regulations I don't think you will find it at significant levels in todays gas. I would worry more about what ethanol will do to your carb parts, the more you can stay away from that the better off your older saw will be.

 

[ckthorp]

I assume "some fuel additives" would include these benzene compounds.

That and alcohols.

 

[djmercer1]

That and alcohols.

i would have assumed that the additives were the over-the-shelf additives.

i would have thought that most of the benzene and other additives in the gas at the pump are assumed to be their as per the astm/csa/asa and other such standards defining the recipe of fuel. typically, with cars anyway, they define the grade of gas and assume/expect you to buy that or better and id expect that is what stihl means here, no e85, etc and at least mid-grade gas.

 

[icelation8]

When the 090 came out at that time it was recommended to use it. With the fuels,oils and emissions of that time thats all it needed I would use mid grade now for best results.

 

[Nailgunner]

I don't imagine over-the-counter fuel additives will have benzene in... they'll have a skull on the bottle if they do and a clear "contains benzene!" sticker.

Far too poisonous to sell in a bottle.

 

[7oaks]

Interesting info

Thanks all for the interesting research. I guess I feel comfortable continuing to use high test in my saws.

...Carl

 

[Bob Wright]

I work in a refinery and we remove the benzene as much as we can while refining the end products...Bob

 

[timberwolf]

Bob, whats the max you can leave in the product? zi think here in Canada gas must be less than 1% benzene by vol.

 

[Bob Wright]

Bob, whats the max you can leave in the product? zi think here in Canada gas must be less than 1% benzene by vol.

I will have to look at the specs when i get to work tonight because right off the top of my head i don't know, plus i am sure its in parts per million...Bob