Type Of Gas

[WVROOKIE]

just a simple concern.My local stihl dealer told me that i should use 89 octane(midgrade) gas in my saw.I told a few old timers that and they told me that im crazy and they've used stihls for 20+ years and with no probs at all...which do you guys use....does the newer motors on stihls require higher octane or should i save the few pennies and get reg unleaded.thanks all

 

[treeclimber165]

Oh, no. You're gonna get Fish all worked up into a tizzy!

Unless you are buying mix gas once per week or more, I'd recommend premium rather than regular. The main reason for my opinion is that premium has fuel stabilizers that are not present in regular gas. I have found that premium gas will stay fresh longer.
The main fuel related problems in two cycle equipment that I have seen is from old gas. Yet I have never had any problem using premium mix gas that was 3-4 months old or older. I know many people (including my neighbor, for whom I just fixed his weedeater and blower) who have problems with old gas because they use regular gas for their two cycle mix.
You are only talking about 10-20 cents per gallon. Not a big deal if you use a couple gallons per week or less. For people who use 5 gallons or more per week using regular will not make much difference.

 

[bwalker]

is that premium has fuel stabilizers that are not present in regular gas.

Brian, I dont know where you got this info, but someone is pulling your leg. The best way to prevent fuel from going bad is to keep it cool and use a metal gas can.

 

[Crofter]

1. What is it about metal vs plastic that contributes to fuel longevity?

2. Is there in fact no difference in stability of low octane vs high octane.

3. Maybe fish was right all along!

Frank

 

[Fish]

I have been experimenting with octane lately, since everyone
on this forum is totally clueless about what it is a measure of.
I have been accuumulating some excellant data, of which
I will share none of it with you all, since it involves higher
mathmatics, like fractions. I did hire on a consultant to
help me, he works for Speedway.
He is an expert on fuel, but since he works third shift, I
thought I would let him sleep a little longer. Besides, he
burnt himself badly making coffee for some truckers this morning
at 4 a.m.
He might not be a top notch consultant, but he does work for a
major fuel company, so he must be right!

 

[bwalker]

What is it about metal vs plastic that contributes to fuel longevity?

The light end boiling point components of the fuel actually boil off and escape right through the pores of the plastic. This process is what causes the great smelling varnish we all know and love.

Is there in fact no difference in stability of low octane vs high octane

For all intents and purposes no. Temperature and the fuel container type have the most influeance on how long a fuel will store. Race fuel sealed in metal cans can last for many years. Another thing to note is gasolines with alcohol and mtbe/etbe store really poorly. Ethanol will draw water vapor from the air right through the walls of a platic tank and cause the fuel to sour. TBE's do not attract water, but they do have low boiling points so the evaporate easily leaving sludge/varnish. So all you people with RFG fuels watch out.

3. Maybe fish was right all along!

I sue premium in all my two strokes. Everything else gets the cheapest rotgut I can find.

 

[mbopp]

"1. What is it about metal vs plastic that contributes to fuel longevity?

2. Is there in fact no difference in stability of low octane vs high octane.

3. Maybe fish was right all along!"

Plastic is permeable, it will allow the lighter hydrocarbons to vent through the wall of the container. I talked to a rep from Nalgene one time (they make plastic fuel bottles for campers and backpackers.) He told me their bottles are made from HDPE with a flouride treatment to reduce the permeability. A tightly capped metal fuel can will keep the lighter elements from evaporating off, hence keeping the fuel fresher.

I don't know about low vs. high octane. My brother is a professional pilot and used to own his own plane. He claims the 100LL av gas had stabilizers added since the relativly low volume of sales meant that the av gas may be in the storage tanks a long time compared to car gas.

Wether Fish is right or wrong is a subject of heated debate, right up there with Stihl vs. Husky and what oil ratio to use.

 

[Fish]

I am usually wrong. The low octane here in Ky. is so volatile
that is can pre-ignite when filling at the pump! We pour
kerosene in our tanks before fueling as a common practice, and
hope it does note preignite before mixing in the tank. we change
plugs weekly, as preignition melts the electrodes within a day
or two.
The lake water here is 122 octane, because I have to dump my old gas and oil somewhere, and the lake is in my backyard.
We have to beat the chainsaw users away, because they like to
mix our lakewater, with their gas/oil mix to raise their octane
rating.
The catfish here have a little bit of an aftertaste, and they have
all developed a real bad attitude, as well as appendages with
opposible thumbs, but after I bludgeon and fillet them, and
throw them in the skillet, they are not that bad.
But I digress.......

 

[sedanman]

Fish, Only two more posts and you are elevated to Grand Pu-bah! And MY lake water is 123 octane so there!

 

[treeslayer]

Fish is nuts.
I would fire my whole crew and hire him twice.
humor value IS all that it is cracked up to be.

 

[Tony Snyder]

Around here most all the gas comes from the same Marathon refinery in nearby Robinson, Illinois. I t delivered to different brands of stations.
They even sometimes put mid grade in the regular tanks because that is what they are carrying.

I have not identified any fuel problems other than stupid mistakes and stale fuel.

 

[dbeck]

There is a station up the road where the price of mid grade is often less than regular. by as much as a nickel sometimes. How is this possible?
i know this is hardly related to what you guyd are talking about, but maybe one of you can answer?

 

[mikek711]

Dbeck.
The only explanation for the price difference is the minimum wage counter jockey putting up the wrong plastic numbers outside on the sign and punching the wrong #'s into the pump computer.....................

 

[treeguy347]

Most stations around here are owned by the same company, so sometimes Admiral (only a couple stations) or one of the independents will cut their prices way below the rest and make the profit based on sheer quantity. This only happens about once a month or so, and they're usually 10-15 cents cheaper.

 

[Rotax Robert]

Although I have never ran into a fuel problem I run 100LL aviation fuel in all my saws from Predator on down to my smaller saws. Costs about $2.50 per gal. around here and the price has not gone up with the cost of regular gas (explain that?)

 

[Harley]

AV gas is not made from petroleum distilates.

It's actually camel pee. That explains why it has such high vapour pressure.

 

[My2cents]

I got some AV fuel a couple of years ago, It was a pain although. I had to chase down the fuel guy at the local airport. People thought I was nuts asking for only 5 gals of fuel. The dispensing mechanism on the truck did notl ike pissing out fuel into a 5 gallon jug. about the same end up on the ground as in my container.

 

[Rotax Robert]

Most small airports that I know have a small pump just like your local gas station. I Probably would refrain from pulling onto the tarmac at kennedy international and trying to chase down a 10,000 gallon fuel truck with your chainsaw. Although I would like to see the video.

 

[My2cents]

By the way he broke my 20 dollar bill directly out of his wallet, rounded it off to the nearest dollar in his favor, and didn't offer a receipt!!