Let’s talk chainsaws

[ancjr]

Picked some of this up today....going to give it a go.

It helps to have the carb adjusted for it as well.

 

[BigRed]

It helps to have the carb adjusted for it as well.

Makes sense... higher octane / lead probably runs rich if tuned for other stuff?

 

[ancjr]

Makes sense... higher octane / lead probably runs rich if tuned for other stuff?

Yes, you can lean it out a bit to get the best out of 100LL and you have to remember you have lower safety margin for running pump gas.

 

[Jaybird1980]

Makes sense... higher octane / lead probably runs rich if tuned for other stuff?

Octane rating doesn't change anything at all as far as rich or lean. The air fuel mixture will need to be the same. Only thing AV gas is doing is removing the ethanol and adding a little lubrication.

 

[ancjr]

Octane rating doesn't change anything at all as far as rich or lean. The air fuel mixture will need to be the same. Only thing AV gas is doing is removing the ethanol and adding a little lubrication.

You can run 100LL leaner (slightly) than you can pump gas.

 

[Jaybird1980]

You can run 100LL leaner (slightly) than you can pump gas.

No. If you can lean it out with 100ll you can lean it out with any other gas. Leaning it out will increase the heat. LL fuel will help provide a little extra protection from that because of the extra lubrication, but if you have already leaned it out to the point of causing damage the lead will not prevent it.

Octane rating has nothing to do with power. It only has to do with compression. Using higher octane fuel than what your engine needs will not increase your power

 

[ancjr]

No. If you can lean it out with 100ll you can lean it out with any other gas. Leaning it out will increase the heat. LL fuel will help provide a little extra protection from that because of the extra lubrication, but if you have already leaned it out to the point of causing damage the lead will not prevent it.

Octane rating has nothing to do with power. It only has to do with compression. Using higher octane fuel than what your engine needs will not increase your power

If all carburetors dispensed all fuels with the same A/F ratio, and all fuels burned the same at the same compression ratio, you'd be 100% correct about carb adjustments.

Also correct that 100LL does not produce more power in itself, but it does open the window for power boosting modifications such as modifying the compression, timing and porting.

 

[Jaybird1980]

If all carburetors dispensed all fuels with the same A/F ratio, and all fuels burned the same at the same compression ratio, you'd be 100% correct about carb adjustments.

Also correct that 100LL does not produce more power in itself, but it does open the window for power boosting modifications such as modifying the compression, timing and porting.

All gases do flow through orifices the same. A carb doesn't flow different octane fuel differently. If the A/F mixture is set correctly for 87 fuel it will be set no matter what octane gas you put in the tank.

Yes if you modified the engines compression you could need a higher octane. Timing and Porting do not alter the octane needs.


Simple.

If you have a higher compression engine that needs higher octane fuel, then running lower octane fuel can lead to pre detonation. Octane is the resistance to the fuel igniting from compression, that is it.

 

[ancjr]

All gases do flow through orifices the same. A carb doesn't flow different octane fuel differently. If the A/F mixture is set correctly for 87 fuel it will be set no matter what octane gas you put in the tank.

Yes if you modified the engines compression you could need a higher octane. Timing and Porting do not alter the octane needs.


Simple.

If you have a higher compression engine that needs higher octane fuel, then running lower octane fuel can lead to pre detonation. Octane is the resistance to the fuel igniting from compression, that is it.

Again, you are correct that the same A/F ratio will result with the same carb setting, if the fuel and air are the same viscosity and density. 100LL doesn't burn the same as pump gas, given the same conditions as pump gas. The second half of your answer is admitting this fact. This is why there is a carb setting difference for optimal combustion.

 

[smokingman]

If you chased down fuel and spark, take a look at the base plate gasket.
I have had to replace a few on older Stihl saws. If it tries to start(runs a stroke or two)and still does not stay running it may be the issue and costs next to nothing to fix correctly.
I 100% agree with everyone saying ethanol free fuel as well.

 

[Jaybird1980]

Again, you are correct that the same A/F ratio will result with the same carb setting, if the fuel and air are the same viscosity and density. 100LL doesn't burn the same as pump gas, given the same conditions as pump gas. The second half of your answer is admitting this fact. This is why there is a carb setting difference for optimal combustion.

Ok, I will try one more time.

The second half of my statement does not apply to homeowner grade chainsaws. @BigRed running 100ll in your saw will not need a carb adjustment unless it needed the adjustment prior, it has no impact on your rich or lean status.

There is no performance gains to be made by running 100ll. The only difference you will notice is better storage life and easier on rubber components because it's ethanol free. If you have Rec-90 closer or cheaper it will provide the exact same benefits.

 

[Leadeye]

100LL is great fuel. I watched as a Bonanza that had set in a hanger for 8 years brought out, tires aired up, bird nests cleaned out, new battery. They turned the key and it fired up on 8 year old gas.

 

[Biggredchev]

Timing is the only adjustment you could make if you are wanting to utilize the higher octane rating. Imo it’s not worth it, it’s a pain to do for not much gain. I run VP 40:1 premix and i noticed more gain from a barkbox and retune than the timing advance.

This G660 is my Guinea pig, i cranked it up to 13,500 rpm and it cuts like mad with a 28” bar and 8 pin sprocket. Is been dang solid for a chinese clone.

 

[Jaybird1980]

Timing is the only adjustment you could make if you are wanting to utilize the higher octane rating. Imo it’s not worth it, it’s a pain to do for not much gain. I run VP 40:1 premix and i noticed more gain from a barkbox and retune than the timing advance.

This G660 is my Guinea pig, i cranked it up to 13,500 rpm and it cuts like mad with a 28” bar and 8 pin sprocket. Is been dang solid for a chinese clone.
View attachment 216934

My back hurts just looking at that thing. Is it just a straight up clone, all Stihl parts fit?

 

[Biggredchev]

My back hurts just looking at that thing. Is is just a straight up clone, all Stihl parts fit?

It’s heafty and also very thirsty lol. Yep, it’s got a stihl clutch, HO oil pump, all the starter parts, the wrap around handle, the WCS dogs and barkbox are for a MS660 and bolted right on. From what ive seen and read, Farmertech buys out of production patents and tooling so everything is compatible with genuine stihl parts. It’s quite nice but i haven’t really had it long enough to recommend.

 

[indyjohn]

Last week, I bought 5 gallons of E-free gas for $4.69/gal in Monrovia. I felt pretty good about myself.

I put Stabil in any gas I store, with or without ethanol. The posts in this thread suggest that is not necessary for the E0 fuel. We haven't been firewooding as much this year as last, and I don't know that I will get through the 5 gallons in the next year or so.

 

[BigRed]

New plug.
Shot of starter fluid in the carb.
Back to running like a Stihl runs!

Swapped fuel to AV...probably just going to stick with that.

I seem to go through periods of heavy use followed by stretches of storage. I have always drained it and ran it to empty before it goes to the rack and have always used stabil, but from what many have told me AV should lend itself better to such.

 

[ancjr]

Ok, I will try one more time.

The second half of my statement does not apply to homeowner grade chainsaws. @BigRed running 100ll in your saw will not need a carb adjustment unless it needed the adjustment prior, it has no impact on your rich or lean status.

There is no performance gains to be made by running 100ll. The only difference you will notice is better storage life and easier on rubber components because it's ethanol free. If you have Rec-90 closer or cheaper it will provide the exact same benefits.

I get it. If it starts and runs it's good enough for most people.

 

[Cameramonkey]

Thats the great thing about chaisaws. They sip fuel, so unless you are felling trees every weekend/week, its not unreasonable to buy canned pure gas/premix for them. Since doing that Ive never had trouble with my saw.

 

[indyjohn]

Thats the great thing about chaisaws. They sip fuel, so unless you are felling trees every weekend/week, its not unreasonable to buy canned pure gas/premix for them. Since doing that Ive never had trouble with my saw.

I did that for a few years and it is easy and convenient. When the OG and I got past cutting that 2nd cord of firewood, I started looking at how much PER GALLON the premix stuff is. Since then I've been mixing the E0 and oil for our saws. Honestly, when fuel is this expensive, the savings is not that significant. But, that is what I'm doing.