Stihl ms260 dies

[kealo]

Hey guys I have an ms260 and I love the saw an it has run flawless for the past two years. I always use the stihl oil and super gas. I was running my saw today pinched the chain bad and the sawjust stopped like I hit the kill switch. Got the saw unstuck and couldn't get it to start. used the choke and it would start and idle but when I pull the trigger it would just die. I cleaned the filter even though I cleaned it before I used it then I pulled the carbs and cleaned everything. Got it running and had to mess with the L and H. It will now idle and run normal for a bit and then dies like it is starved of fule so I back off the trigger for a bit and roll it on to the clutch side and then it would go again and so on.

Questions are.
1could I have damaged the cylinder with the sudden stop?
2can the fuel pump just stop working like that diafram leak?

Any help would be great thanks

 

[CK-1]

When you cleaned the carb(s) did you blow out the port holes? How about the fuel filter?... Have a cheap Poulan that stopped work last year. Pulled and cleaned the carb. with new filter but it wouldn't stay idle... I will order a new carb when I get around to it.

 

[Senatormofo]

Sounds like a fuel problem to me. I doubt pinching the blade would cause starting problems. Can't imagine any cylinder issues from it either. I just (tonight) put a carb gasket kit on an 11 year old Shihl that was giving me problems starting and idling. It started on the second pull and runs great now. Good luck my friend!

 

[jeff_t]

What's the fuel line look like?

 

[kealo]

I blew some air down the fule line and it shot lots of fuel back out. Spayed carb clean and blew out the ports The fule line looks good. It is just weird that I cut down and chunked a whole tree and then was 1/2 way through the second tree and this happened. I guess I will try a carb kit. Does any one know what the L and H are supposed to be set at? The H only turns 3/4 of a full turn and the L does a compleat turn?

 

[HittinSteel]

The ms 260 fuel line is the only fuel line I've had to replace on a newer saw...... failed in less than 2 years from new. I'd start there like others have said.

 

[smokinj]

Replace your fuel filter. Your l and H scew probally will need tune again once up and running good enough. Should be no damage on the piston. I can dead stop an 880 at will.

 

[MasterMech]

Fuel line is a good first target, look to see if it holds pressure or just replace it. I'd look close at the intake boot as well. It's possible it could have torn or pulled off slightly when the saw stopped or you were wrestling it free.

 

[Dingeryote]

Before you even do anything.

Pull the muffler and eyeball the piston. Not saying you scuffed anything, but if you did, fussing with anything else will be pointless.

Check the tank vent. They get kinked sometimes, especially while tinkering with carbs.
Replace the fuel filter if you havn't already.

Check the fuel line for cracks...flex the line and use a magnifying glass to be sure. Dadgum Ethanol kills fuel lines and they get tiny cracks every 2-3 years on some, others go longer, and are inconsistent when they start showing up.

Double check the rest of the lines bieng secure on the nipple. Ethanol hardens lines and they don't flex as well over time, and thus, leak just enough air to make a guy go nuts figuring it out.

It sounds very much like our MS250 and old 026 when they have a bad fuel line. The cracks in the line would seal untill vibrated just right...drove me nuts untill I just got torqued and replaced the lines, THEN I noticed the teeny little cracks when flexed.

Set the "H" all the way to the stop rich.
Set the "L" half way through it's travel and plan on tinkering to find best response without puddling while idling for a Min.
Then set High to 4 stroke unloaded, but to clean up with slight pressure in the cut.

Good luck to ya!!

 

[Sorghum]

Check-replace the impulse line. My 026 Pro did the same thing.Just plain stopped running while in the middle of a cut. The estimate repair price scared me, so I bought another saw. A year later I decided to let them take a closer look at the 026, and it was just the impulse line. Had that and a couple of other minor things done for under $50.00.

 

[Danno77]

sudden pinch in wood. can't rev it up? have you looked at your clutch? could be as simple as a broken spring.

 

[kealo]

I dropped it at the dealer and they said they can't get it to run and needs a new carb. $75. We will see if it works. Need the saw back lots of work to do.

 

[cygnus]

I dropped it at the dealer and they said they can't get it to run and needs a new carb. $75. We will see if it works. Need the saw back lots of work to do.

So? What's the verdict? Did the carb do the trick?

 

[Clarkbug]

How are your AV mounts? I only ask because if they are loose you could maybe have torn or unseated the rubber boot between the carb and the cylinder, and that could be an issue I suppose. I guess the dealer has it, so they would know better, but seems odd that your carb would suddenly just go bad....

 

[mo381]

I have had similar problems after pinching the bar. Make sure your bar tip/nose sprocket doesn't have wood wedged in it stopping it from turning freely.

 

[Danno77]

Your dealer takes too long or you are holding out on us!

 

[kealo]

so i finally got it back last week after the dealer had it for a month and it seems to work fine with the new carb..they claimed with all the bad fuel these days and the new carbs with small check valves that are not serviceable they have to replace the carb.. The only problem i have is that while 260 was being fixed i borrowed my brothers 034 and had a hard time giving it back.. man that was a nice saw but the little 260 still holds its own...

 

[mking7]

A new carb? That's not at all what I was guessing. I was going with tank vent but the pinched bar thing made me back off that.

I like my 260 at times but after running my 361 and 260 back to back both with brand new chains, I won't be picking up my 260 as much.

 

[MasterMech]

so i finally got it back last week after the dealer had it for a month and it seems to work fine with the new carb..they claimed with all the bad fuel these days and the new carbs with small check valves that are not serviceable they have to replace the carb.. The only problem i have is that while 260 was being fixed i borrowed my brothers 034 and had a hard time giving it back.. man that was a nice saw but the little 260 still holds its own...

Lemme translate that outta dealer-speak for you....

"We don't have a technician that can reliably clean and rebuild a carb fast enough to make it worthwhile. Since we don't want to see the saw come back and need to make money, we take the far more profitable route of replacing the entire carburetor, at your expense of course."

Just curious, how much was that carb? Some carbs on low-end trimmers and blowers are dirt cheap (BG55 carb is roughly $35) and therefore not worth rebuilding but IME that's usually not the case with a pro-grade saw like the MS260. I have never seen a saw carb with the check valves built-in/non-serviceable. The valves are part of the diaphragms in the carb which are easily replaced. There are check valves in the primer assembly of some carbs that are not accessable but you can usually replace only the primer base. Your 260 doesn't have a primer so I know that wasn't an issue.

Glad to hear you're up and running again.

 

[Woodsrover]

Like MM said, there aren't any check valves in these little carbs. It's done with the gaskets and diaphragms. He's also right that these guys just don't know how to take one of these apart. I'm sure it could have been torn down and cleaned up and back to running without replacing anything. Oh well, next time learn to tear it down yourself. It's not a big deal.

One thing they were right about is the crappy fuel these days. I'm new here so I'm not sure if it's been discussed but I keep a 5-gallon can of VP "Small Engine Fuel" around and run it in my saws that don't get used all that often. I have and run a lot of different saws and some sit for a while with gas in them. The new gas would eat them up in short order. Likewise, in the winter or spring when I'm not going to be cutting for a while, the last tank of fuel is always SEF. (Same goes for all my small engines....Leaf blowers, string trimmers, etc.) It's ethanol-free and doesn't absorb water like regular gas. Sta-Bil has a good marine-grade fuel stabilizer that works pretty good too.

Good choice on the MS260. It's my favorite saw. The 361 and 460 are great saws too, but I the 260 is the one I most often reach for.