How Often Do You Adjust Your Carb?

[Chainsaw]

I’ve got a couple of auto tune Husqvarna’s and a bunch of normal carb’s chainsaws. Thinking about a Stihl MS 261 and debating the mtronix vs standard carb offering. I guess the auto tune type saws are the cat’s meow these days, but reflecting back over the years, aside from some initial adjustments to rid the chainsaw of an initial lean condition, I really don’t find myself ever adjusting the carb summer or winter.

What about you - are you constantly going to the woods with a chainsaw and small screw driver to adjust your carb?

Makes me think, while auto tune is good, is it really necessary?

I’m leaning towards the standard carb MS 261 in as much as that is an option. The Husqvarna’s that I have are only available with auto tune.

Thoughts?

Thanks!

 

[singinwoodwackr]

I’ve got a couple of auto tune Husqvarna’s and a bunch of normal carb’s chainsaws. Thinking about a Stihl MS 261 and debating the mtronix vs standard carb offering. I guess the auto tune type saws are the cat’s meow these days, but reflecting back over the years, aside from some initial adjustments to rid the chainsaw of an initial lean condition, I really don’t find myself ever adjusting the carb summer or winter.

What about you - are you constantly going to the woods with a chainsaw and small screw driver to adjust your carb?

Makes me think, while auto tune is good, is it really necessary?

I’m leaning towards the standard carb MS 261 in as much as that is an option. The Husqvarna’s that I have are only available with auto tune.

Thoughts?

Thanks!

Unless you change elevations on a regular basis the carb should be just fine for years.

 

[EFSM]

I’ve got a couple of auto tune Husqvarna’s and a bunch of normal carb’s chainsaws. Thinking about a Stihl MS 261 and debating the mtronix vs standard carb offering. I guess the auto tune type saws are the cat’s meow these days, but reflecting back over the years, aside from some initial adjustments to rid the chainsaw of an initial lean condition, I really don’t find myself ever adjusting the carb summer or winter.

What about you - are you constantly going to the woods with a chainsaw and small screw driver to adjust your carb?

Makes me think, while auto tune is good, is it really necessary?

I’m leaning towards the standard carb MS 261 in as much as that is an option. The Husqvarna’s that I have are only available with auto tune.

Thoughts?

Thanks!

It depends on what level of performance you expect from a saw. Temperature, humidity, and barometric pressure differences, as well as elevation changes, will affect the tuning of a saw, but usually not enough for the average saw user to notice. A properly working carburetor with an effective air cleaner system that doesn’t clog all the time will need tuned only when temperature changes exceed 70 degrees, in my experience. I already tested WOT rpm’s of a saw, same gas, same tune, same log, on successive days when the temperature changed 50+ degrees due to a weather system. The rpm’s were within 2% of each other. I’m sure some saws vary more, but that has been my experience when using properly working saws.

 

[drf256]

Many later factory saws came w non-adjustable H jets. That has to mean something.

I have personally found that saws with larger exhaust outlets need more frequent tuning. I’m not sure if it’s a factor of the actual exhaust scavenging, or just that I can hear the tune better. My old style of tuning was so terrible, yet my saws lasted. I’d go for peak RPM, then fatten it 1/8 turn. Somehow nothing ate itself.

I have a friend w a stock 038M that hasn’t ever turned a single carb screw since he purchased it new in the 90’s.

I have found that the more into saws I became, the more I tune them. I try to keep them nice and fat for people with limited saw knowledge. They also make more torque that way.

Autotune saws are great when running correctly. They adjust continually for peak performance while cutting. I don’t think a human ear can beat that.

 

[Coupe]

When it needs it yes but not just the fun of playing with thee L/H screws.
As above when the saw is running nicely why play with it.

 

[bucketofguts]

Not much on my saws but I found this quote "
A 2019 study by the U.S. Forest Service found that improperly tuned carburetors account for over 30% of chainsaw-related mechanical failures."

 

[bwalker]

I’ve got a couple of auto tune Husqvarna’s and a bunch of normal carb’s chainsaws. Thinking about a Stihl MS 261 and debating the mtronix vs standard carb offering. I guess the auto tune type saws are the cat’s meow these days, but reflecting back over the years, aside from some initial adjustments to rid the chainsaw of an initial lean condition, I really don’t find myself ever adjusting the carb summer or winter.

What about you - are you constantly going to the woods with a chainsaw and small screw driver to adjust your carb?

Makes me think, while auto tune is good, is it really necessary?

I’m leaning towards the standard carb MS 261 in as much as that is an option. The Husqvarna’s that I have are only available with auto tune.

Thoughts?

Thanks!

If you want the saw to perform as designed you have to tune the carb.

Get the Mtronic IMO.

 

[bwalker]

Unless you change elevations on a regular basis the carb should be just fine for years.

No, a carb cant compensate for temperature, fuel, etc.
If you run an adjustable carb saw and want it to run right it has to be tuned regularly.
When I use to log it was common to set the carb on a cool fall morning and then have to do it again at noon when it warmed up.

 

[bwalker]

It depends on what level of performance you expect from a saw. Temperature, humidity, and barometric pressure differences, as well as elevation changes, will affect the tuning of a saw, but usually not enough for the average saw user to notice. A properly working carburetor with an effective air cleaner system that doesn’t clog all the time will need tuned only when temperature changes exceed 70 degrees, in my experience. I already tested WOT rpm’s of a saw, same gas, same tune, same log, on successive days when the temperature changed 50+ degrees due to a weather system. The rpm’s were within 2% of each other. I’m sure some saws vary more, but that has been my experience when using properly working saws.

A twenty degree swing in temp is a big differance.
When I was logging I tuned every morning minimum.

 

[bwalker]

Many later factory saws came w non-adjustable H jets. That has to mean something.

I have personally found that saws with larger exhaust outlets need more frequent tuning. I’m not sure if it’s a factor of the actual exhaust scavenging, or just that I can hear the tune better. My old style of tuning was so terrible, yet my saws lasted. I’d go for peak RPM, then fatten it 1/8 turn. Somehow nothing ate itself.

I have a friend w a stock 038M that hasn’t ever turned a single carb screw since he purchased it new in the 90’s.

I have found that the more into saws I became, the more I tune them. I try to keep them nice and fat for people with limited saw knowledge. They also make more torque that way.

Autotune saws are great when running correctly. They adjust continually for peak performance while cutting. I don’t think a human ear can beat that.

The Stihl MS260 Pro had a fixed jet Carb. At least some years did. The saw was a complete turd with that fixed jet carb. Install a WT194 and mod the muffler and it was a whole new saw performance wise.
Tuning a saw to the factory max no load and then enriching another 1/8 is a recipe for a pig rich saw. It will last no doubt, but it will also run like crap.

 

[jacktheripper]

I’m always giving things a tweak here or there. Big bar in big wood, more richer. Drive 30 minutes and I’m up at 10k ft, less richer. Temp dropped below freezing, more richer. Limbing, less richer. Etc.

 

[Duane(Pa)]

The Stihl MS260 Pro had a fixed jet Carb. At least some years did. The saw was a complete turd with that fixed jet carb. Install a WT194 and mod the muffler and it was a whole new saw performance wise.
Tuning a saw to the factory max no load and then enriching another 1/8 is a recipe for a pig rich saw. It will last no doubt, but it will also run like crap.

He said peak rpm, not factory max no load... I have had hated saws that I intentionally tried to kill/blow up with carb screws. No joy. Probably a testament to my mix, but they didn't die (free revving). I'm never totally happy with my tune if a have a screwdriver in my pocket. Temp or fuel quality are the only things that might change, as I only cut on my own property.

 

[jacktheripper]

All my actual “user” saws have a scrench holder on the handle. I drill a hole in it and stick a Stihl screwdriver in it too.

 

[bwalker]

He said peak rpm, not factory max no load... I have had hated saws that I intentionally tried to kill/blow up with carb screws. No joy. Probably a testament to my mix, but they didn't die (free revving). I'm never totally happy with my tune if a have a screwdriver in my pocket. Temp or fuel quality are the only things that might change, as I only cut on my own property.

Is that what he meant?

 

[Duane(Pa)]

Yes. As you said, a saw would be very difficult to do any work with if tuned 1/8 turn rich of factory max no-load. 1/8 turn rich of screaming like a banshee may be pretty decent... Too many variables lol! Where have we heard that before?

Is that what he meant?

 

[larasea]

I have (2) MS261c. (1) DOM 2018 has M-Tronic 2. (2) DOM 2023 has M-Tronic 3. I like the M-3 over the M-2. The M-3 has 6 tanks thru it and it was starting hard. Did a recalibration and fixed the starting issue and running strong.

I have 10 Stihl saws. 5 are M-Tronic and would not have anything but M-Tronic.