Stihl MS261cm starting issues - less than 6 months old

[laddo]

So I bought a brand new Stihl MS261cm in October of 2020 from my local dealer. I just started my arborist service and used it weekly. After about a month, it was used daily, but not like hardcore production work or anything like that. Me and my 1 man crew used it on every job.

I thoroughly clean the saw each weekend and use Stihl’s premium mix oil at a 50:1 ratio.

Anywho, this week we had some unusually low temperatures in South Louisiana and I made sure to flip the shutter to winder mode. All was going well. Until 2 days ago the damn thing started acting up crazy every time I tried to start her. Even if the engine is already warm, it will take 4-5 pulls on choke to get a quick rev that putters out as soon as you touch the trigger. You do that 2 or 3 times and you kind of feel like you might be making progress and then out of nowhere it all goes to absolute shit and wont start at all.

When that happens, I go through the carb reset process listed in the manual and the saw will run fine until I shut it off again. Then I basically start the entire process over.

-I checked the fuel filter, it seems clean and fine
-air filter looks fine and is cleaned weekly
-I have no reason to suspect the fuel because my other saws are fine

Please help


• Aim High, Climb Trees •

 

[Reach]

I would take it back to the dealer and let them figure it out. It should still be under warranty; if it’s not, and you have a decent relationship with your dealer they’ll probably fix it for free anyway.

 

[Crimsonking]

I’ve not run many 261s, but the ones I’ve used have had the same issue. I’m curious to hear what you learn.

 

[evo]

I had a spark plug failure on mine a few weeks ago. The problem was intermittent and it would run fine for a moment then stumble and cut out, flood and all sorts of crap like that.
Took it to the shop and they said “spark plug gap too wide”. And put a new one in. I thought this was really strange as the saw isn’t very old.
They give me the old parts, and I open the package and eyeball the plug. It looked fine. Talked with the guy a bit and started to put the plug away, the gap was completely closed, turned it upside down and it was wide open.

The little electrode broke loose inside the plug.

Cost me way too much $ for such a dumb repair, but also very glad the saw didn’t eat it and it’s floating around somewhere in the engine

 

[DeadHead]

I had this issue in the really hot months last year. From all the siding around I did I settled on it being a solenoid.

I just threw away the card that had the part number on it.

 

[adolan]

We've been going through a lot of spark plugs on our new 261cs and 201ts. All dealer supplied plugs but it has been an issue for the last few months.

 

[Phil]

it being a solenoid.

This. Welcome to the wonderful world of Mtronic. We have 2 of the 261s at work. I use them regularly. Both are down for this issue.

 

[Gorman]

Even when hot you must set the switch to choke when starting.

 

[Dan Cobb]

Just out of curiosity, what version number of M-tronic do you have?

 

[laddo]

Just out of curiosity, what version number of M-tronic do you have?

Where can I find that info? I just bought the saw in Oct 2020


• Aim High, Climb Trees •

 

[Dan Cobb]

Where can I find that info? I just bought the saw in Oct 2020


• Aim High, Climb Trees •

I looked at the manual on line. It shows the version number as the last 3 characters in the string of characters on the right side of the approval label on the saw. "M3.0" indicates version 3.0.

 

[Jehinten]

Where can I find that info? I just bought the saw in Oct 2020


• Aim High, Climb Trees •

Here on the rear handle. It's listed at the bottom center of the pic in the anti section. M3.0 on my 261

 

[Dan Cobb]

Seems the consensus is that v3 is better than 1 or 2. I'm interested in this thread as I'm contemplating purchase of a 261. Still pondering M-tronic or not, assuming both are locally available. M-tronic sounds good if it's reliable. I'll be the only one using the saw, so I'm not concerned about the proper procedures not being followed. Speaking of that, how did you know which of the 2 different calibration procedures (page 44) to follow if you didn't know which M-tronic version you have? Must be a nightmare for companies that have a mix of M-tronic versions to keep track of which procedure to follow based on tiny numbers on a label that may get obliterated.

Also noticed the manual doesn't even call it a "choke position." It's the "start position."