Premium or regular unleaded

[ForestGrump]

Sorry to disagree with you, but do not compare a rinky dink independent refinery to the "majors".
You stated the drivers were adding the additive there selves; WOW, that would NEVER happen at any reputable refinery. Yes, adding a pint to a car tank of gas would not be a good idea. The federal government only states you have to add a detergent/cleaner to keep the intake system clean. Well, one drop could be considered adding a detergent. Amoco had an extensive research and testing facility in Naperville. They knew what and how much to add without a doubt. All loading at the rack was computer controlled and each brand; Amoco, BP, Chevron, Exxon, Shell etc had there own additive package at our loading rack. When a driver carded in to load they got their company additive in the correct amount decided by their company. If a no name truck (jobber) came in to load they got a basic additive package and the minimum amount. I still work for a "major" oil company and I am one of the gas blenders. ( I make it ) Pretty sure I have a good understanding of whats going on. Even DEWFPO backed my original statement.
My rule is, I only buy gas from branded "majors". It may cost more but I have NEVER had a fuel related problem in any vehicle I've ever owned. That means the mom and pop gas station that has a "major" brand is off limits for me. They will buy from the cheapest spot they can and add anything to the tank including water. Yes, that has been done.
So I will reaffirm my original statement of buying the gas your owners manual states to put in. The engine compression ratios were engineered for a specific octane. More octane (to a degree) will not hurt the engine but it will not help either.

Just wondering what "major" refiner do you work for? Did a quick looksee for current refiners in Utah, all were pretty small and I remember seeing Chevron, the only major. I still work for and consult for one of the majors you mentioned.

 

[DEWFPO]

The manufacturer's and dealers recommend 91 octane for all small two cycle engines for high altitude use.

That's interesting because less octane is required for higher altitudes due to the reduction in compression pressures. In fact, fuel stations here sell 85,87 and 91 octane as compared to the higher octane fuels the counties below 4,000 get.

DEWFPO (lives at 7,100')

 

[ForestGrump]

That's interesting because less octane is required for higher altitudes due to the reduction in compression pressures. In fact, fuel stations here sell 85,87 and 91 octane as compared to the higher octane fuels the counties below 4,000 get.

DEWFPO (lives at 7,100')

I bought three new large Stihl chainsaws, and brought two in for repairs, and they told us to switch to premium, which we did. It seemed to make a difference in their longevity.

 

[buickanddeere]

If the engine is knocking and pinging , it isn't going to last .

 

[ForestGrump]

They were not knocking or pinging. They took 87 octane but the dealer recommended we switch to 91.

 

[sawtooth]

They were not knocking or pinging. They took 87 octane but the dealer recommended we switch to 91.

Check your manual but some Stihl products recommend at least 90 Octane. Also I only use 100% gas in my small engine equipment. Unless your refilling each tank every month ethanol gas with cause you problems long term. Download the app called "pure gas" to locate your nearest 100% gas dealer. Your equipment will thank you.

 

[ForestGrump]

I live on a mountain. We had access to a private gas and/or diesel pumps but gas only in regular. So we had to go to one of the 3 local stations for 91. The stihl dealer recommended 91 for high altitude use for their 87 octane 2 cycles. We complied, we liked, the saws liked.

 

[MossRoad]

Thread pruned of politics. Please take it to the friendly politics forum. Thanks.

 

[ForestGrump]

Thank you!

 

[buickanddeere]

They were not knocking or pinging. They took 87 octane but the dealer recommended we switch to 91.

You can't hear the knock and ping from a typical small two stroke engine, it is there and real. Look at the damage, broken rings, crushed ring lands, scored cylinder walls and holes burned through pistons. That ain't a lack of oil, in fact it can be caused by too much oil which lowers the fuel octane .