Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Husqvarna => Topic started by: 3000 FPS on January 14, 2014, 04:10:08 pm

Title: Husqvarna K760 cut off saw.
Post by: 3000 FPS on January 14, 2014, 04:10:08 pm
I have been working on a lot of cut off saws lately and worked on this K760 today.   It is the craziest design for getting to the carb that I have come across yet.    You have to take the rear handle off of the saw just to get to the carb.    Any one here ever work on one of these and know any easier way of getting it apart.
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on January 14, 2014, 04:37:24 pm
I do a lot of those too, and no there is no other way! The worst part is that it will be back before you know it! The concrete weenies REFUSE to use the water jet and dont change/clean the filter, they just use it until it quits. On top of that they just throw it in the back of the truck covered in concrete dust, then it rains and every stinking one of the T-27 Torx screws has its head full of concrete that you have to pick out with a dental probe before you can even work on the f$%&#ing things.

I hope your boss is getting a lot of money to do those things!
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on January 14, 2014, 04:44:00 pm
I do a lot of those too, and no there is no other way! The worst part is that it will be back before you know it! The concrete weenies REFUSE to use the water jet and dont change/clean the filter, they just use it until it quits. On top of that they just throw it in the back of the truck covered in concrete dust, then it rains and every stinking one of the T-27 Torx screws has its head full of concrete that you have to pick out with a dental probe before you can even work on the f$%&#ing things.

I hope your boss is getting a lot of money to do those things!

Ok thanks for the reply.   I just wanted to confirm that.    Yes my boss does alright on these saws for repairing them.   I just did a piston and cylinder on a K970 also which I did not consider to be to bad of a job but these K 760 are a different story.   
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on January 14, 2014, 04:53:21 pm
Yes any of the 760s are a HUGE PITA! Roger, my heart goes out to ya! The old yellow Partner branded ones are pretty easy but the new orange Husqvarna branded ones are a pain.
Title: Re: Husqvarna K760 cut off saw.
Post by: Eccentric on January 14, 2014, 08:39:06 pm
Fabulous.  I'll be working on one of these soon..... :-\
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on January 14, 2014, 08:53:57 pm
Have fun, they only have a 2 yr warranty for a reason, they are generally shot within 18 months! Shot to the point that repairing them is not economical at lest if they are being used to cut concrete or stone. Actually, I like Husqvarnas but Stihl makes a better saw for this purpose! :'(
Title: Re: Husqvarna K760 cut off saw.
Post by: Eccentric on January 14, 2014, 09:02:04 pm
Have fun, they only have a 2 yr warranty for a reason, they are generally shot within 18 months! Shot to the point that repairing them is not economical at lest if they are being used to cut concrete or stone. Actually, I like Husqvarnas but Stihl makes a better saw for this purpose! :'(

Yeah I'm not looking forward to messing with the damn thing.  As you stated earlier, they're usually abused to no end.  When they're a bugger to work on (like this design) AND abused like that...............well it's the makings of a good time.  That's actually not a Husqvarna design.  I wish Husky still sold the older cutoff saw designs that were based on their chainsaws (such as the 268K, 272K, 371K, 372K, 375K, and 3120K).
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on January 14, 2014, 09:08:21 pm
Have fun, they only have a 2 yr warranty for a reason, they are generally shot within 18 months! Shot to the point that repairing them is not economical at lest if they are being used to cut concrete or stone. Actually, I like Husqvarnas but Stihl makes a better saw for this purpose! :'(

Yeah I'm not looking forward to messing with the damn thing.  As you stated earlier, they're usually abused to no end.  When they're a bugger to work on (like this design) AND abused like that...............well it's the makings of a good time.  That's actually not a Husqvarna design.  I wish Husky still sold the older cutoff saw designs that were based on their chainsaws (such as the 268K, 272K, 371K, 372K, 375K, and 3120K).

Is it a Partner design?
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on January 14, 2014, 09:09:49 pm
Well the older Partners are close to the HVA K series saws but are much easier to work on than the current version. Have a good time! I have a 760 under the bench that has been sitting there since September last, just can't get into it!
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on January 14, 2014, 09:11:01 pm
Have fun, they only have a 2 yr warranty for a reason, they are generally shot within 18 months! Shot to the point that repairing them is not economical at lest if they are being used to cut concrete or stone. Actually, I like Husqvarnas but Stihl makes a better saw for this purpose! :'(

Yeah I'm not looking forward to messing with the damn thing.  As you stated earlier, they're usually abused to no end.  When they're a bugger to work on (like this design) AND abused like that...............well it's the makings of a good time.  That's actually not a Husqvarna design.  I wish Husky still sold the older cutoff saw designs that were based on their chainsaws (such as the 268K, 272K, 371K, 372K, 375K, and 3120K).

Is it a Partner design?

I believe so!
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on January 14, 2014, 09:12:41 pm
Well I took this thing all apart today and then put all back together, got it running and tuned it, only to find out the kill switch is not working.   So tomorrow I will do it all again.
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on January 14, 2014, 09:41:10 pm
I believe that the kill switch is one of those spring metal types like on a  home owner saw. Sometimes the get a little sprung and just need to be bent a little so the tab makes contact with the spring. This usually happens when you are struggling to get the carb/cylinder off.
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on January 14, 2014, 10:02:00 pm
I believe that the kill switch is one of those spring metal types like on a  home owner saw. Sometimes the get a little sprung and just need to be bent a little so the tab makes contact with the spring. This usuall happens when you are struggling to get the carb/cylinder off.
Ok I will check it out.
Title: Re: Husqvarna K760 cut off saw.
Post by: Eccentric on January 14, 2014, 10:20:17 pm
Have fun, they only have a 2 yr warranty for a reason, they are generally shot within 18 months! Shot to the point that repairing them is not economical at lest if they are being used to cut concrete or stone. Actually, I like Husqvarnas but Stihl makes a better saw for this purpose! :'(

Yeah I'm not looking forward to messing with the damn thing.  As you stated earlier, they're usually abused to no end.  When they're a bugger to work on (like this design) AND abused like that...............well it's the makings of a good time.  That's actually not a Husqvarna design.  I wish Husky still sold the older cutoff saw designs that were based on their chainsaws (such as the 268K, 272K, 371K, 372K, 375K, and 3120K).

Is it a Partner design?

Yep.
Title: Re: Husqvarna K760 cut off saw.
Post by: Magnus on January 15, 2014, 02:28:47 am
Partners last design was the cubic ones that ended with 650 series. They had no design of their own after Elux, but HVA pretty much went on the same track until fresh air engines came to be.

The 750 series is Husqvarna design straight thru.
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on January 15, 2014, 01:32:18 pm
Finished taking the K760 apart today and putting it back together with the kill switch fixed.   I am glad that is done.
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on January 15, 2014, 02:41:09 pm
OK Roger, so what was the problem with the kill switch?
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on January 15, 2014, 03:06:22 pm
Some one had been in this saw before and the ground wire was broken.   I ran another wire from the switch to ground.  This saw had screws missing stripped threads for the starter cover, you know some one just messing around with it and did not know what  they were doing.  I put it back together with some blue Loctite in a few places.
Title: Re: Husqvarna K760 cut off saw.
Post by: Eccentric on January 15, 2014, 03:45:05 pm
Partners last design was the cubic ones that ended with 650 series. They had no design of their own after Elux, but HVA pretty much went on the same track until fresh air engines came to be.

The 750 series is Husqvarna design straight thru.



In the US, that series of cutoff saws have been badged/sold as Partner up until a few years ago.  For a number of years before that.......they were branded as Partner (while Husqvarna cutoff saws were models based on their chainsaws, such as the 268/272K, 371/375K, and 3120K machines).  That's why I'd stated that these machines were a Partner design. Looks like they were designed by Husqvarna to be sold as Partner (and later Husqvarna) branded machines.  Splitting hairs...

http://www.ebay.com/itm/PARTNER-K700-ACTIVE-III-CUT-OFF-SAW-DEMO-CONCRETE-CEMENT-ROOFING-NEW-BLADE-/191031903663?pt=Concrete_CutOff_Saws&hash=item2c7a6385af

http://www.ebay.com/itm/husqvarna-k750-concrete-cut-off-saw-Demo-saw-Demolition-Partner-K750-Chop-Saw-/331101637700?pt=Concrete_CutOff_Saws&hash=item4d17320c44

http://www.ebay.com/itm/PARTNER-GAS-POWERED-CUTOFF-SAW-K950ACTIVE-/121081145954?pt=Concrete_CutOff_Saws&hash=item1c30ffaa62

http://www.ebay.com/itm/Husqvarna-K1250-Concrete-Cutoff-Saw-SIZE-14-/331103771579?pt=Concrete_CutOff_Saws&hash=item4d17529bbb

http://www.ebay.com/itm/2-New-CYLINDER-PISTON-RINGS-Kits-Husqvarna-Partner-K960-K970-Cutoff-Saw-56mm-/261264492977?pt=LH_DefaultDomain_0&hash=item3cd493c9b1

http://www.ebay.com/itm/2-New-CYLINDER-PISTON-RINGS-Kit-Husqvarna-Partner-K750-K760-Cutoff-Saw-51mm-/261334925687?pt=LH_DefaultDomain_0&hash=item3cd8c68177

http://www.ebay.com/itm/HUSQVARNA-PARTNER-1250-K1250-CUT-OFF-CONCRETE-CHOP-SAW-REWIND-STARTER-RECOIL-/290660604779?pt=LH_DefaultDomain_0&hash=item43acb8db6b

http://www.ebay.com/itm/Husqvarna-Partner-starter-assembly-complete-506235903-NEW-NOS-cut-off-saw-k950-/151208594309?pt=LH_DefaultDomain_0&hash=item2334bc0b85

Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on January 15, 2014, 04:05:49 pm
Roger, is that the black wire that is trapped under a screw in the carb box that holds the flat contact spring? Sometimes it is possible with forceps to fish a new wire without dismantling the saw.
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on January 15, 2014, 04:15:22 pm
Roger, is that the black wire that is trapped under a screw in the carb box that holds the flat contact spring? Sometimes it is possible with forceps to fish a new wire without dismantling the saw.

Yes that was the one.   It's all done now, but the problem is getting that top section free that sits above the carb so you can see what the heck the problem is and fixing it.   
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on January 15, 2014, 04:44:10 pm
Don't I know it!!! The designers, really did not intend the saw to be worked on, IMHO. It is as if they planned and designed for the saw to be worn out before the warranty period is up and cost-to-repair would greatly exceed cost-to-replace! What a world we live in!! Husqvarna is the LAST company I would expect to have adopted this mind set!

I have worked on lots of old HVA designs that used the old red on/off switch that have never messed up, it seems that lately everyone is trying to design their products so that the end user does not have to think. They come up with designs for a simple switch that are FAR to complex for the job at hand, creating a maintenance/service/reliability nightmare! Shades of the German Tiger tank!
Title: Re: Husqvarna K760 cut off saw.
Post by: Magnus on January 16, 2014, 05:54:51 am
Partners last design was the cubic ones that ended with 650 series. They had no design of their own after Elux, but HVA pretty much went on the same track until fresh air engines came to be.

The 750 series is Husqvarna design straight thru.



In the US, that series of cutoff saws have been badged/sold as Partner up until a few years ago.  For a number of years before that.......they were branded as Partner (while Husqvarna cutoff saws were models based on their chainsaws, such as the 268/272K, 371/375K, and 3120K machines).  That's why I'd stated that these machines were a Partner design. Looks like they were designed by Husqvarna to be sold as Partner (and later Husqvarna) branded machines.  Splitting hairs...

http://www.ebay.com/itm/PARTNER-K700-ACTIVE-III-CUT-OFF-SAW-DEMO-CONCRETE-CEMENT-ROOFING-NEW-BLADE-/191031903663?pt=Concrete_CutOff_Saws&hash=item2c7a6385af

http://www.ebay.com/itm/husqvarna-k750-concrete-cut-off-saw-Demo-saw-Demolition-Partner-K750-Chop-Saw-/331101637700?pt=Concrete_CutOff_Saws&hash=item4d17320c44

http://www.ebay.com/itm/PARTNER-GAS-POWERED-CUTOFF-SAW-K950ACTIVE-/121081145954?pt=Concrete_CutOff_Saws&hash=item1c30ffaa62

http://www.ebay.com/itm/Husqvarna-K1250-Concrete-Cutoff-Saw-SIZE-14-/331103771579?pt=Concrete_CutOff_Saws&hash=item4d17529bbb

http://www.ebay.com/itm/2-New-CYLINDER-PISTON-RINGS-Kits-Husqvarna-Partner-K960-K970-Cutoff-Saw-56mm-/261264492977?pt=LH_DefaultDomain_0&hash=item3cd493c9b1

http://www.ebay.com/itm/2-New-CYLINDER-PISTON-RINGS-Kit-Husqvarna-Partner-K750-K760-Cutoff-Saw-51mm-/261334925687?pt=LH_DefaultDomain_0&hash=item3cd8c68177

http://www.ebay.com/itm/HUSQVARNA-PARTNER-1250-K1250-CUT-OFF-CONCRETE-CHOP-SAW-REWIND-STARTER-RECOIL-/290660604779?pt=LH_DefaultDomain_0&hash=item43acb8db6b

http://www.ebay.com/itm/Husqvarna-Partner-starter-assembly-complete-506235903-NEW-NOS-cut-off-saw-k950-/151208594309?pt=LH_DefaultDomain_0&hash=item2334bc0b85



Yea, brand is one thing. You can put what ever color and sticker on it, it is still same design.. Brand is Partner, but built by Husqvarna/Elux and their engineers.  Partner designs went out the tube when the brand was bought a long time ago. Elux/Husqvarna continued series as long as they could then had to design a new one with fresh air engine and this is what they came up with.
Title: Re: Husqvarna K760 cut off saw.
Post by: Eccentric on January 16, 2014, 02:46:04 pm
Unfortunately what the Elux/HVA engineers came up with is a lousy design, at least from a service perspective...
Title: Re: Husqvarna K760 cut off saw.
Post by: Magnus on January 16, 2014, 03:16:40 pm
I fully agree. One filter solutions?

I had a couple broken cases and a bunch of cooked saws here. No fun.
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on July 21, 2014, 10:58:00 pm
I worked on 3 more K 760's today all had scored pistons and cylinders and all came from the same place.   I suspect straight gas.
Title: Re: Husqvarna K760 cut off saw.
Post by: aclarke on July 21, 2014, 11:43:32 pm
After dealing with a rash of straight gas failures, we took the employees out of the loop on buying "mixed gas"  not a single seizure in 6-7 years!!
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on July 22, 2014, 12:08:16 am
After dealing with a rash of straight gas failures, we took the employees out of the loop on buying "mixed gas"  not a single seizure in 6-7 years!!

Smart move.   I have 5 more cut off saws to look at tomorrow all from the same place and I have a bad feeling.
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on July 22, 2014, 08:07:08 am
Good luck Roger, I do not envy you!
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on July 22, 2014, 08:10:54 pm
I had one more K760 that was good and 4 Stihl cut off saws.    All the Stihls were runners when I was done
Title: Re: Husqvarna K760 cut off saw.
Post by: KilliansRedLeo on July 23, 2014, 06:59:37 am
What model Stihl? Actually Roger, I believe the Partner/HVA saws have a poor filtration system design compared to Stihl. Almost every one I see has some sort of C/P scoring. The other thing is that the users NEVER seem to use the built in water spray when cutting, perhaps the use of the water which is designed to keep the dust down would contribute to the longevity of the saw by sort of helping the filter system out? Rarely do I see a Stihl with scoring unless it is raw gas related.
Title: Re: Husqvarna K760 cut off saw.
Post by: SawTroll on July 23, 2014, 12:06:47 pm
What model Stihl? Actually Roger, I believe the Partner/HVA saws have a poor filtration system design compared to Stihl.  .....

Sounds odd - as until recently it was the other way around with chainsaws.

However, we are of course talking about a totally different kind of dust with cutoff saws, so it could well be true anyway.
Title: Re: Husqvarna K760 cut off saw.
Post by: 3000 FPS on July 24, 2014, 12:41:26 am
What model Stihl? Actually Roger, I believe the Partner/HVA saws have a poor filtration system design compared to Stihl. Almost every one I see has some sort of C/P scoring. The other thing is that the users NEVER seem to use the built in water spray when cutting, perhaps the use of the water which is designed to keep the dust down would contribute to the longevity of the saw by sort of helping the filter system out? Rarely do I see a Stihl with scoring unless it is raw gas related.

The Stihls were 2 TS 400 one TS 420 and a TS 510.   The 510 was a big heavy saw with a 12" diamond blade on it.   When I revved that thing up it was like hanging onto a large gyroscope.
 The scoring I found in the Huskys was severe and had to be caused by a lean condition or straight gas.    I did find a Husqvarna 970 I believe it was, where cement dust had worked into the throttle shaft of the carb and it started to wallow out causing an air leak.
  I agree with you on the water.   These things have so much cement dust in them it is a wonder they still worked at all.
Title: Re: Husqvarna K760 cut off saw.
Post by: Eccentric on August 01, 2014, 09:04:55 pm
I still haven't gotten into the Partner K700 that's been sitting on my shop floor for months.  It'll need a new P/C methinks............so I may just part it out on the bay. 

Would like to have a good runner cutoff saw of that size however.  I have a Target Q65-14 that's based on a McCulloch 795L.  At 103cc and somewhere around 30 pounds it's a beast.

I see that there's some aftermarket P/C sets out for the K700................but am skeptical of the quality.  For now I think it'll remain on the shop floor...
Title: Re: Husqvarna K760 cut off saw.
Post by: 630 red on August 02, 2014, 04:07:59 pm
to remove the carb, with air filter removed there is a stud through plastic housing remove it, pop the throttle rod from trigger. lift up take off fuel pipe  that should be it be careful putting back to line up choke lever.