Posted: 3/26/2009 4:43:47 PM EDT
One of the bright lights I work with decided he knows better than Husqvarna and ran a brand newHusquvarna/Partner K750 concrete saw on straight gas rather than the correct two cycle mix, with the result that the engine gave up the ghost and quit and wouldnt restart no matter what. The dealer quoted hundreds of dollars to repair and mgmt decided to chuck it out so ––-I grabbed it after I got it apart I found that he had cracked a piston and the peice of skirt had locked up under the connectig rod and i think the skirt piece blocks off the intake port of the cyl as it goes up––something like that
anyway my question is I know i have to replace the piston. but do i need to replace the cylinder ––most of it looks Ok and still has the croshatch from the factory hone 
except for the part where the piston skirt cracked and there is some really minor scoring 
that looks in that pic much worse than it is in reality. The diffrence is about $150.00 parts cost ––- $200 for cylinder assembly w/ piston and gaskest-versus $50 approx for just the piston and gaskets can I gert away with just replacing the piston ? |
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Well, it's hard to tell from the pic but if the scoring isn't too deep (.005 max) you might be able to get away honing it. But will probably end up buying a cylinder anyway. Depending on what rings cost, what I would probably do is buy the new piston and rings, hone the cylinder and try it. If it's not right, no harm no foul, buy a new cylinder (and probably another new set of rings) and give it another go. |
You might consider also posting your question on the PERR Small Engine Technical Forum - the ARFCOM of small engines! 
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Thanks guys I will probably go ahead and get the cylinder assembly (approx$200.00) which is the cyl/piston/rings/rod pin/retainers/needle bearing for the connecting rod/gaskets and seals.
the piston/rings and gaskets run $50 or so.The scoring is not real bad but I hate to do something half assed or twice. Even if I spend the $200 and get it back together I am ahead of the game cause I got a saw for $200 that can go for $1100.00 new ––-AND I dont have to pay the co M&E charges on it when i use it on a job ( they assess you a $50 charge for co owned equipment used on a job––cut saws jackhammers and the like) so in 4 jobs it would essentially pay for itself. Its this one here Husky K750 IIRC the last time I bought a 14in diamond blade ––that alone was almost $200 |
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Quoted:
It needs the cylinder too. If you don't replace the cylinder, the thing will smoke like a B-model Mack, right up to when it grenades again. It needs new rod bearings, too. maybe you can tell me why it is going to smoke like a B-model truck???? It is a two cycle engine. It is going to smoke anyway... But yes you are right in all other aspects.. I think I would try to hone the cylinder if the scoring isn't too deep.. What you got to lose other then time. Just make damn sure you get any sharp edges honded smooth then it probably won't damage the new piston.. Try the piston in the bore after honing and before the rings are installed..to make sure they are no tight spots.. Some engines the bore is not hard all the way through they are esentially case hardened and the hardness is only a couple thousandths deep. if the scoring is deeper then that go with the new cylinder... |
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Ebay is your friend. Here is one for parts..... at $39 right now.
Parts... Piston and Rings.... $30 plus S&H Piston Kit Piston and Cylinder Kit.... 189 plus S&H Piston and Cylinder Good luck! |
its alive-ALIVE!...ALIVE!!
Need to clean it up now i took it outside and chopped up some cinder blocks with it. Yes it lives–– got the parts this am priority mail, got home tonite at 6:15 and by 8 pm it was up and running. This was one of the most intuitive and easy to assemble peices of power equipment I have seen Husqy did ahellof ajob engineering this thing. I took a box of parts and fasteners I did NOT take apart––was not 100% sure all of the parts were there––and in two-three hours put it together having never worked on one before and it runs like a scalded ape . heres how good husqy designed this thing ––you can take it apart down to its component peices and put it all back together with one tool ––this––- 
Once I got it all together I took it out filled it with fuel/mix (50:1) and after about six pulls with the choke on it burbled then I kicked the choke in to half choke and pulled it agian and she fired right up. I wanna thank all you guys for your good advice and help. Off to the carwash for a good cleanup for this mutha! |
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This was one of the most intuitive and easy to assemble peices of power equipment I have seen Husqy did ahellof ajob engineering this thing. I took a box of parts and fasteners I did NOT take apart––was not 100% sure all of the parts were there––and in two-three hours put it together having never worked on one before and it runs like a scalded ape . heres how good husqy designed this thing ––you can take it apart down to its component peices and put it all back together with one tool
Good job man! I've had to do that repair to a couple of saws, glad you could get yours to work for cheap. Give Partner all the credit for the design though, as much as I love Husq. all they did was buy up Partner a year or so ago. |
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LOL which concrete saw do you use for zombies??
or 12" or 14"––- RPM vs. cutting depth––which do you prefer?
Yep it is partners design ––thats true all the parts are made in Sweden now though.––most are marked as such, is a helluva saw either way. Now all I have to do is save M&E charges on 3-4 jobs(the co hits me 50-100 bucks to use a co tool on a job "SUPPOSEDLY" for maintenence& equipment costs––it never gets used for that..) and this thing is paid for wheras if i bought it outright retail I would have to use it on about ten seprate jobs before it would be paid for. In that respect it does make life easier trying to make a concrete driveway look good after a sewer excavation is difficult when you dont saw cut the edges of the hole.Some guys just jackhammer the hole and try to feather out the concrete but it looks like crap and within a year or so you can see the ragged edges of the hole in the concrete. |