261 c-m running LEAN?

[chipper1]

I'm running ethanol free gas plus Echo Powerblend at 40:1 in my 261c and have for 3 years. I cut year around and the only issues I've had are hot start when the temps are 105F + (and only then when I don't let idle for a few seconds before shutoff or if placed directly in the sun for a while). I also run this in my newer 261c and my 441c with no issues.

I don't think your fuel ratio is the issue. Just my two cents...

I forgot to say I run the free too, but I think I did earlier in this thread.
Yesterday I was thinking about letting it run a bit before shutting it off when the 201 acted up. That's fine when they have plenty of fuel in them, and I guess I could get away with it when they run out as there is usually a good bit left, but I have a habit of shutting them down as soon as I hear them surge at. It was 45 here yesterday when I was cutting so I don't think that had anything to do with mine acting up. I don't recall having a problem like this on the later 550's often, the earlier ones would act up, but just as the 201 they would straighten out. I have noticed this on standard carb saws now and then, maybe a small bubble in the fuel line that doesn't get purged out or something, but this seems to be something separate from the OP's problems.
Those 441c sure are nice runners , and smooooth.

 

[MountainHigh]

I wonder if there is an issue with running a stronger mix, possibly fouling sensors? I've ran 50:1 premix in mine from the start.

That's an interesting thought. Yet with others having no 40/1 issues and my Autotune 562xp seems to handle 40/1 non-ethanol/94 octane with ease, it's certainly not conclusive. Maybe a specific run of MAF sensor?

Canadian Stihls are made in Germany and if memory serves US Stihls are made in US ?

 

[EchoRomeoCharlie]

That's an interesting thought. Yet with others having no 40/1 issues and my Autotune 562xp seems to handle 40/1 non-ethanol/94 octane with ease, it's certainly not conclusive. Maybe a specific run of MAF sensor?

Canadian Stihls are made in Germany and if memory serves US Stihls are made in US ?

MAF as in Mass Air Flow?

My understanding of Mtronic is that it's essentially an auto adjusting carb, no need for a MAF as it's not fuel injection. Carb still works as carbs do, it's just that the saw watches the RPM, which it does through the control module, and adjusts fuel accordingly to maintain maximum rated RPM by adjusting the jets via electronics.

Maybe I'm misunderstanding, but I don't believe a oil mix ever touches a sensor in Mtronic. The only real 'sensor' it has is the control module/coil system. Fuel doesn't touch that.

 

[MountainHigh]

MAF as in Mass Air Flow?

My understanding of Mtronic is that it's essentially an auto adjusting carb, no need for a MAF as it's not fuel injection. Carb still works as carbs do, it's just that the saw watches the RPM, which it does through the control module, and adjusts fuel accordingly to maintain maximum rated RPM by adjusting the jets via electronics.

Maybe I'm misunderstanding, but I don't believe a oil mix ever touches a sensor in Mtronic. The only real 'sensor' it has is the control module/coil system. Fuel doesn't touch that.

I'm definitely not an expert on these auto carbs (or any carb for that matter), but whatever sensors do exist (module/coil) that regulate the mix, might they be the culprit? I would be happy to hear more thoughts from those with more mechanical know how than I.

 

[farmer steve]

That's an interesting thought. Yet with others having no 40/1 issues and my Autotune 562xp seems to handle 40/1 non-ethanol/94 octane with ease, it's certainly not conclusive. Maybe a specific run of MAF sensor?

Canadian Stihls are made in Germany and if memory serves US Stihls are made in US ?

Never gave that a thought. May have something to do with how they are set up.
I know the 462's that were getting sent over from Greece were set up a little different.

 

[SuperDuty04]

Yeah i wasn't saying they had a maf, just that maf cleaner may be an option to clean any electronic sensors IF the mtronic system had any. But it sounds like it just adjusts off of rpm's.

 

[MountainHigh]

Was hoping to give my 261cm a good run today but the rain is putting an end to that idea.

 

[farmer steve]

Was hoping to give my 261cm a good run today but the rain is putting an end to that idea.

Ran all the Mtronic saws today. Took the 261 about 8 pulls to start from cold. About 28* this morning. Did a bunch of cutting on some dead ash. No problems with any saws.

 

[MountainHigh]

Ran all the Mtronic saws today. Took the 261 about 8 pulls to start from cold. About 28* this morning. Did a bunch of cutting on some dead ash. No problems with any saws.View attachment 775282 View attachment 775283

Nice pile of wood!

My saw beat your 8 pulls on cold start. Went out in the rain after all and filled the truck with a load. Only took the 261cm with me so it was do or die. Mine started on 5 pulls from cold and I ran almost a tank through. Ran well and restarted several times on 1 or 2 pulls max. Hit some dirt and had to sharpen chain and it took 8 pulls without the choke after chain sharpening on back of tailgate. Maybe it needed to be choked again (or whatever the cold start position is) and will try that in future.

So far so good ... the light weight is really nice when bush wacking on hillsides. Sorry no photos - I was drenched. Warm fire sure nice to come home to.

 

[L34]

Not to derail but I have a 441c that is hard to start cold.
After reading this thread I done a drop start,easiest it has started.
Chris.

 

[MountainHigh]

Not to derail but I have a 441c that is hard to start cold.
After reading this thread I done a drop start,easiest it has started.
Chris.

Ya, my 261cm seems to like a hard kick as well. Not sure if it`s saw specific or a Stihl thing.

 

[MountainHigh]

Thought I'd try a cold drop start this morning - saw had 1/5 tank of 50/1 Stihl premix remaining from yesterday. Temperature is a balmy 9 celcius or 48.2 F.

Took a disappointing 9 pulls drop start to pop, then fired and ran on 10th.
This saw needs a purge bulb!

Like the weight, like the performance, but if I can't figure out a way to make this start more easily, she'll be out the f'in door soon.

 

[KiwiBro]

Finally had a chance to run the 261 again today. Took a bit to start but ran fine and started fine when warm. Not sure what's up. Will try a cold start later on today.

 

[Gypo Logger]

That's an interesting thought. Yet with others having no 40/1 issues and my Autotune 562xp seems to handle 40/1 non-ethanol/94 octane with ease, it's certainly not conclusive. Maybe a specific run of MAF sensor?

Canadian Stihls are made in Germany and if memory serves US Stihls are made in US ?

It seems that any Stihl chainsaw made in Germany will have the numeral 1 as the first digit in the serial #. Those with a 2 or 5 were assembled in Virginia Beach.
The larger saws are all built in Germany. Strangely enough the MS 201 is only built in Germany.
Stihl chain is built in Switzerland.
I’m not sure if the 261 was built both in Virginia and Germany, but I suspect that all Arctic saws are built only in Germany.

 

[Gypo Logger]

Getting back to the 261 with excessive heat or the lack there of. There’s a winter/summer baffle in the air box as all other saws have.
I’ve left mine in the summer position as the winter position allows bug dust to enter the air box and probably snow as well. It’s an Arctic so it has a heated carb anyway so I can’t see that it needs any warm air introduced into the air box from the cylinder.
Any thoughts?

 

[Gypo Logger]

Also if you remove your clutch cover and scrape all the crud off and if you see stamped in the metal, “If a tree falls in the forest, does anybody hear?”, then it was definitely made in Canada.

 

[EchoRomeoCharlie]

Thought I'd try a cold drop start this morning - saw had 1/5 tank of 50/1 Stihl premix remaining from yesterday. Temperature is a balmy 9 celcius or 48.2 F.

Took a disappointing 9 pulls drop start to pop, then fired and ran on 10th.
This saw needs a purge bulb!

Like the weight, like the performance, but if I can't figure out a way to make this start more easily, she'll be out the f'in door soon.

I don't know what the temp differences were between the two days, or how hot the saw was when you put it away...but maybe your tank vent isn't working properly and it's pulling a vacuum inside the tank? This will be especially problematic when you have a hot saw and let it sit with a small amount of fuel in it. Air in tank gets cold, pulls vacuum, tank vent isn't allowing it to equalize which causes hard starting as you'll have to overcome the vacuum in the tank by pulling.

For a free 'test' you could open the fuel tank cap before attempting to cold start and see if the average pulls it takes to start gets more consistent.

 

[trains]

I don't know what the temp differences were between the two days, or how hot the saw was when you put it away...but maybe your tank vent isn't working properly and it's pulling a vacuum inside the tank? This will be especially problematic when you have a hot saw and let it sit with a small amount of fuel in it. Air in tank gets cold, pulls vacuum, tank vent isn't allowing it to equalize which causes hard starting as you'll have to overcome the vacuum in the tank by pulling.

For a free 'test' you could open the fuel tank cap before attempting to cold start and see if the average pulls it takes to start gets more consistent.

Yeah, its certainly sounding like issues with the fuel being drawn up to the carb, thus the high amount of pulls when cold before it burps.
Whats the top side of the fuel pump diaphragm like, full of bits not allowing the pump to flex and pump as it should ?
have seen bits accumulate there from bad fuel, or left for long periods of time, and thus poor operation of the fuel pump in the carb.

 

[MountainHigh]

I had opened the gas cap to check on the amount of fuel the day it needed 10 pulls to run. Temp on the day I put it away was about the same as the next. Next chance I get will let you know. I appreciate the feedback.

My 261 cm had a sticker with bar code on it saying Made in Germany -will check for the serial.

 

[MountainHigh]

It seems that any Stihl chainsaw made in Germany will have the numeral 1 as the first digit in the serial #. Those with a 2 or 5 were assembled in Virginia Beach.
The larger saws are all built in Germany. Strangely enough the MS 201 is only built in Germany.
Stihl chain is built in Switzerland.
I’m not sure if the 261 was built both in Virginia and Germany, but I suspect that all Arctic saws are built only in Germany.

Little Miss 261 c-m prissy gal started cold with decomp on 6 easy pulls today (no drop start required). She even 4 stroke burbled a bit out of the cut (can I get an A-men! Hallelujah).

After warmed up she restarted 3 times with no decomp on first pull. Used decomp another time and she took 3pulls warm start. Seems to be getting her sea legs.

Serial begins with a 1 so she's a German build alright.

I told her I'm a patient man, but don't tease me too long or you'll be out walking the streets looking for a new place to call home.