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Worst luck ever-Brand new Husqvarna K760 running rough without power

Started by woodworker9, August 27, 2017, 12:33:40 PM

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woodworker9

For 10 years or so, my luck with concrete saws was great.  I use the synthetic oil, mix new gas/oil frequently, and never leave fuel in my saws (or chainsaws) for any length of time.  My luck seems to have run out this year.

As in the other thread, I was having continued problems with my older, but usually trusty K750.  I decided to sort that problem out later, and just buy a brand new saw...K760.  With help from Joe and this forum, I sorted out the issue with the K750, so I am not "out of business" at the moment.  Still, a brand new saw with troubles is quite the hair pulling experience for me.

The saw ran great the first two times I used it.  Then, this past Thursday, I was cutting a control joint between two slabs (I'm a concrete raising contractor) to free them up so I could raise the settled side back to level.  When the joint free'd up, the high side of the concrete dropped down (very common occurrence) and pinned the blade.  The saw shut off immediately and abruptly, which my other saws (26 years experience doing this) have never done.

Using the usual method of carefully prying the blade out of the joint, I free'd the saw.  Started it back up again, and now it won't run worth a darn.

Here's the symptoms;  absolutely no power running, and very hard to keep running.  Wants to die out quickly, and hard to get up to speed.  If I choke the saw partially, it runs better, but as soon as I push the choke in, it wants to die down and run with no power at lower rpm's.

Even though I always run new fuel, with synthetic Stihl oil, I emptied fuel, and mixed a fresh batch.  No change.  I let the saw run at idle for about 15 minutes, and it improves slightly, but still not running correctly.  After a 2 hour cool down, a fresh cold start resulted in the exact same problem, and a brand new, fresh spark plug did not cure the problem.

This is a brand spankin' new K760 with less than a total of 1 hour of run time on it. 

I purchased it from an ebay seller, as the only "Husqvarna" dealer local to me is an absolute joke.  He's worked on two of my previously owned Stihl saws, made almost no improvement to both of them, and still charged me an excessive amount for the work.  He stocks no parts, not even maintenance filters, plugs, etc......and when it comes to talking to him about a problem with anything, alls he wants customers to do is drop the tool off.  ZERO help, and quotes 2 to 3 weeks for everything, even when he knows it's more like 6 to 8 weeks before anything gets done.

So, please don't tell me to take it to the local dealer.  In this case, that is just not an option for me.  I'd rather ship it to one of you guys on my dime than give that idiot a chance to screw up another machine of mine.

So, back to the issue, if there's something that you great folks can recommend that I try before shipping off this saw for repair, I'd really appreciate the help.  I don't know what else I can do at this end, as I'm completely stumped.

Jeff
03' LT40HD25 Kohler hydraulic w/ accuset
MS 441, MS 290, New Holland L185

dougand3

Your current symptoms sound like fuel delivery issue, carb tune, clogged air filter or clogged muffler screen. Hard to believe any of those happened instantly on a 1 hour run time saw. So, blade stops abruptly and saw dies. Did clutch stay engaged? Crankshaft bent? Bearings buggered up? Massive air leak?
You can check the simple things but I suspect there is a need to dig deep into saw.
Husky: 372xt, 272xp, 61, 55 (x3)...Poulan: 315, 4218 (x3), 2375, 2150, 2055, 2000 (x3)...Stihl 011AVT...Homelite XL...Saws come in broken, get fixed or parted, find new homes

celliott

Does this saw have the oil guard feature? I read about it on the husky site- there is a light sensing diode that reads the oil- to make sure a saw isn't straight gassed. Thing is, it only works with a special husqvarna oil that has a special dye in it. If that oil wasn't used (you said it was Stihl oil) Maybe it would run poorly, kind of like a limp mode? Just a thought, if it's a brand new saw.

Also pretty sure the feature can be disabled so you can run any oil you want- think it was marketed more for rental places or large industrial users with lots of careless operators.

Just read the husky site again, this does sound pretty likely. Probably it ran fine for the first hour on the gas from the dealer?

Here's a link.

http://www.husqvarna.com/us/products/power-cutters/k-760-with-oilguard/967181402/
Chris Elliott

Clark 666C cable skidder
Husqvarna and Jonsered pro saws
265rx clearing saw
Professional maple tubing installer and maple sugaring worker, part time logger

ladylake

 I'd be checking the flywheel key, that abrupt stop could have sheared it.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

sawguy21

old age and treachery will always overcome youth and enthusiasm

woodworker9

Quote from: ladylake on August 27, 2017, 04:44:33 PM
I'd be checking the flywheel key, that abrupt stop could have sheared it.  Steve

How would I go about doing that, if you don't mind telling me?  I'm good mechanically, but not familiar with these, as changing the ignition module on my other saw is the only thing I've ever had to do.

To answer the other questions, the saw didn't have oil it from the dealer, as I didn't buy it from a local dealer.  I purchased it online, and it was shipped to me.  Brand new, never had been run or even had gas in it.  Ran perfectly on my usual gas/oil mix of Stihl synthetic for the two times in use.  After the abrupt stop incident, I've had trouble ever since.

I'll check the parts breakdown in the manual for this sheer key and see if I can easily get to it.

Thanks for the input.
03' LT40HD25 Kohler hydraulic w/ accuset
MS 441, MS 290, New Holland L185

woodworker9

Quote from: celliott on August 27, 2017, 04:40:54 PM
Does this saw have the oil guard feature? I read about it on the husky site- there is a light sensing diode that reads the oil- to make sure a saw isn't straight gassed. Thing is, it only works with a special husqvarna oil that has a special dye in it. If that oil wasn't used (you said it was Stihl oil) Maybe it would run poorly, kind of like a limp mode? Just a thought, if it's a brand new saw.

Also pretty sure the feature can be disabled so you can run any oil you want- think it was marketed more for rental places or large industrial users with lots of careless operators.

Just read the husky site again, this does sound pretty likely. Probably it ran fine for the first hour on the gas from the dealer?

Here's a link.

http://www.husqvarna.com/us/products/power-cutters/k-760-with-oilguard/967181402/

Well, shoot.  I didn't even know about this, but it sounds like my saw is suffering the same symptoms.  I will check tomorrow.  As stated, I didn't buy it from a dealer, but from an ebay seller.  I need to check into this.  Thanks.
03' LT40HD25 Kohler hydraulic w/ accuset
MS 441, MS 290, New Holland L185

PNWRusty

I like the sheared fly wheel key theory.

Unless you fueled it between the time it jammed to a stop in the cut and it started running poorly. But it doesn't sound like you did. And why would any lack of oil failsafe device allow the saw to run at all?

woodworker9

I did some reading. Oil Guard, as it is called, reads a dye in Husqvarna Oil and when it digitally detects the dye marker in the oil, allows the saw to run at max. rpm's.

When the 'Oil Guard' detection system doesn't detect the dye, it limits the saws rpm's to 3800 rpm's, which doesn't kill it, but does not allow full power for use.

My saw has no indication that it has this system, as the telltale insignia tag is not on the saw, and neither is the tab that you can remove/break off to disable the system.

I was not even aware that system was around when I purchased the saw.  I didn't spend my usual 'due diligence' when buying, as this was an immediate need, hasty purchase.  I simply chose the cheapest seller for a Brand New saw, and this one was it.  The seller included a nifty red metal carrying box, labeled "Husqvarna", along with 2 brand new diamond blades of decent quality, 2 abrasive cut off wheels, a Husqvarna hard hat, ear muffs, and safety glasses, as well as a 1 gallon, nice quality, metal fuel cannister for carrying oil/gas mix.......all for the nice, tidy sum of $700.00, with free 2 day shipping.  My local dealer wanted $975.00, plus tax, with none of the extra's.

I will read the parts manual that came with the saw, and see if I can figure out how to access this sheer pin you guys are talking about.

Any other thoughts are appreciated.
03' LT40HD25 Kohler hydraulic w/ accuset
MS 441, MS 290, New Holland L185

Texas-Jim

Its not actually a shear pin as a rule. Its a key made into the flywheel that assures flywheel cant move. If it moves it will alter the timing and machine may not run well or at all. On stihl there is a nut in center of the flywheel, just remove it and check to be sure that key isnt sheared off. Often a sudden stop from high rpm will allow  the flywheel to spin and shear it off. Its easy and cheap to check it. If its the problem the flywheel is not cheap. Not sure if yours is the same but most stihl's are made into the flywheel so if it shears you have buy entire flywheel.
What we do in life echoes through eternity.

woodworker9

Ok.  I just removed the flywheel.  Tapered bore.  The sheer pin is intact, so that's not it.

Good try, though as it had all those bad timing symptoms.

What's next?  Any ideas...?
03' LT40HD25 Kohler hydraulic w/ accuset
MS 441, MS 290, New Holland L185

hamish

Norwood ML26, Jonsered 2152, Husqvarna 353, 346,555,372,576

joe_indi

Inspect the spark plug. In a concrete cutter with constant high revs it should be gray and dry. Is yours dry or wet?
Remove the air filter and start it. If it revs you can attribute the cause to a restricted air. Some of these new saws have new fangled electronic stuff shoved into it that could play up, like a speed limiter.
I have not seen the Husky concrete cutters but there is a remote possibility that a chainsaw coil (372 or 365) might be a straight fit, maybe even the one from your other cutter.
If possible swap the coil and try it. Dont bother about the stop switch wires. Dont connect them, You can stop it with the decompression if required. Right now you are trying to start it so stopping it is not a priority.

woodworker9

After a long conversation with Husqvarna technical service, I drove the saw about 45 minutes away to a certified service center.

I'm a bit miffed, as I was sold a "new saw" online that is actually a new, never used 2010 model.  I had no idea that I would have to verify the year of a saw listed for sale as "brand new, in the box".  That's on me, I guess.

Anyway, after a lengthy conversation with Husq., as of now, they agreed to have a certified service shop look at it after I provided proof of purchase that it was purchased new.

We'll see how this one goes.  If the saw is returned to me running and usable, I'll chalk it up to an experience to remember, and move on.  In the end, the only thing that matters to me is having a usable tool for work.

I am sharing this embarrassing transaction only as a reminder to others that, I guess, we now have to check every last detail when buying online.....even the serial number of a new saw.
03' LT40HD25 Kohler hydraulic w/ accuset
MS 441, MS 290, New Holland L185

woodworker9

Just to finalize the thread, thanks to all for helping me out.

The dealer tech pulled the carb and cleaned it.  The saw runs perfect now.

No charge for the work...warranteed from Husqvarna.   I didn't expect that, and am happy to just have it back earning it's keep.
03' LT40HD25 Kohler hydraulic w/ accuset
MS 441, MS 290, New Holland L185

thecfarm

Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

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