guys
Dumpster Diver
Posts: 20
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Post by guys on Mar 21, 2019 14:48:28 GMT -5
So often we learn things the hard way! Such as fuel mixture %. I have a Homelite 540 chainsaw and I’m in need of a piston & pin set part # A00790. If anyone out there has one and will sell it to me we can keep one more Homelite running. I've tried Bob Johnson and not luck. Guy S
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matt540
Collector
Homelite 540
Posts: 60
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Post by matt540 on Mar 21, 2019 16:46:20 GMT -5
Hello Guy. What fuel ratio mixture are you running? Did your saw seize up? I run my 540 at a 40:1 ratio and I know there is a whole other thread on fuel ratio mixtures. Everyone is different and has their own opinions on this. From what I understand it can be difficult to find a piston for a 540. Hopefully someone has a source they are willing to share with you to find the parts you need. Luckily, I am knocking on my wood work desk, I haven't needed to put a new piston in my saw.
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Post by scotts2000 on Mar 21, 2019 17:29:32 GMT -5
Pistons are scarce for those... I just sold a parts saw and a runner ...saw was in great shape just had bad piston cylinder ...not worth fixing ...the cost of the cylinder and piston are nuts if available.
Fuel mixture is only half the battle. You need to be able to tune to run on the mixture your running.. I dont want to start a fuel debate but i personally run 50:1 and have had great luck. I always have gone through my saws first and tuned according... Even a 32:1 oil mixturre can be leaned out and burn up a saw..
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guys
Dumpster Diver
Posts: 20
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Post by guys on Mar 21, 2019 17:34:13 GMT -5
That was the first thing Bob Johnson asked me. I told him I thought they were all the same and he replied H no. He said the same thing everyone has there on idea, but if were my saw I would be running 32 to 1. Of course I was running it at 50 to 1. I did almost got the project done. I wanted to remove an Oregon Ash tree from my front yard and got all but the 24" cut. At the base the tree was 43" thru. As I stated when I joined the forum this saw was my brothers and now I feel bad about what my lack of knowledge has none to it. Bob has made numerous phone calls to help me but no luck. if I could even find the ring set for it I might be able to have the piston turned? The rings set part number is 12659A Guy S
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Post by Clasec on Mar 21, 2019 23:42:52 GMT -5
That was the first thing Bob Johnson asked me. I told him I thought they were all the same and he replied H no. He said the same thing everyone has there on idea, but if were my saw I would be running 32 to 1. Of course I was running it at 50 to 1. I did almost got the project done. I wanted to remove an Oregon Ash tree from my front yard and got all but the 24" cut. At the base the tree was 43" thru. As I stated when I joined the forum this saw was my brothers and now I feel bad about what my lack of knowledge has none to it. Bob has made numerous phone calls to help me but no luck. if I could even find the ring set for it I might be able to have the piston turned? The rings set part number is 12659A Guy S www.ebay.com/itm/678036001-Genuine-Homelite-Piston-Ring-540-UT10550-UT100550-Chainsaw/170788741063?hash=item27c3cd5fc7:g:QiQAAOxyaRZR0e0W
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guys
Dumpster Diver
Posts: 20
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Post by guys on Mar 22, 2019 0:23:38 GMT -5
I did see that add for the piston set on eBay however my 540 is UT-10611 & UT-10612. The set I'm told is a part number A00790. From the looks of my cylinder I might be able to hone it. As I was cutting I realized the engine was going to stall so I shot it off. Guy S
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Post by scotts2000 on Mar 22, 2019 10:07:44 GMT -5
I did see that add for the piston set on eBay however my 540 is UT-10611 & UT-10612. The set I'm told is a part number A00790. From the looks of my cylinder I might be able to hone it. As I was cutting I realized the engine was going to stall so I shot it off. Guy S Also before repair of cylinder and piston please look for orginal problem... Check for air leaks. Crankcase seals and intake boot tend to be a source of lean outs. A clean carb with proper tuning. Scott
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guys
Dumpster Diver
Posts: 20
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Post by guys on Mar 22, 2019 13:13:12 GMT -5
I installed a brand new carburetor and intake boot worm gear and felt seal. I’ve never tuned it. I adjusted the high ideal and the ideal. The cases were tight with no oil leaks. The spec sheet says the cylinder is aluminum with chrome plated bore (can one hone that type cylinder?) dose anyone out there have any suggestions as far as parts connections? Guy S
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Post by edju1958 on Mar 22, 2019 13:35:38 GMT -5
I'd advise you NOT to hone the cylinder only because you can take too much of the chrome plating off & it'll be worn down to the aluminum making the cylinder useless.Your best bet is to take the cylinder off where you can have a good look to detrrmine if it's salvageable.Once the cylinder is off you can clean up the aluminum transfer.I did this by using a sheet of 80 grit emery cloth wrapped around a section of 1 3/4 PVC pipe.I took my time inserting it in the cylinder & then you can only turn it one way.There were a couple of small spots that I had to really work at to get the transfer off,but within an hour I had it looking like new.Then I went over it with 120 grit emery cloth & finally 320 grit.Get some pics on herer & let us see what it looks like. Ed
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Post by undee70ss on Mar 22, 2019 14:12:49 GMT -5
Pull the muffler and post some pics of the piston. You need to determine what went wrong first before buying anything. It sounds like it was running lean but we are all just guessing without pics.
Regardless of what oil ratio one uses, any saw should be tuned first for the ratio YOU are using and your conditions. Out of the cut, it should "4 stroke" and run smooth in the cut.
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guys
Dumpster Diver
Posts: 20
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Post by guys on Mar 22, 2019 17:06:53 GMT -5
I’ve been trying to post some pics to no avail. I’m trying to drag the images as well as download the file from my photo file to HOH. Just not letting me. I’ll have to get some help. Hang in there with me please. Guy S
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Post by undee70ss on Mar 22, 2019 17:44:16 GMT -5
I’ve been trying to post some pics to no avail. I’m trying to drag the images as well as download the file from my photo file to HOH. Just not letting me. I’ll have to get some help. Hang in there with me please. Guy S PM sent
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guys
Dumpster Diver
Posts: 20
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Post by guys on Mar 25, 2019 12:10:43 GMT -5
the cylinder is not scored much. Do you think the piston can be cleaned up? The rings were stuck at one end but I was able to remove both of them . definitely need a ring groove file done to it..I
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guys
Dumpster Diver
Posts: 20
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Post by guys on Mar 25, 2019 12:44:42 GMT -5
more pics of my scored piston
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guys
Dumpster Diver
Posts: 20
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Post by guys on Mar 25, 2019 13:05:12 GMT -5
This is the worst side. T Attachments:
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Post by sweepleader on Mar 25, 2019 13:28:21 GMT -5
I would concur that honing a plated cylinder is not a good idea. I would just work on the areas where there is aluminum transferred from the piston. Neither piston nor cylinder look too horrible. If the rings were stuck they could easily be a compression problem and you might get away with reusing the piston and cylinder if they were cleaned up.
Be very careful "filing" in the ring groove, you do not want the rings flopping around loose in there. If one spot is too wide, the ring will break from fatigue in short order, if the whole groove is too wide, the land will break out of the piston. A broken ring can be used to lightly scrape any build up from the groove, if you have one. It is the right width and can gauge the progress of your work. If you don't have one it can be a tricky job keeping the groove square and the right size all around.
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Post by undee70ss on Mar 26, 2019 2:15:40 GMT -5
Given how hard parts are to find for this saw, I would remove the transfer from cylinder, clean up piston, some new rings and run it. As Dan said, be very careful on the ring grooves, they are most likely tight where the scoring is. Measure the size where a new ring fits well to go by. If you take to much off, piston will be ruined. Saw did run lean, so make sure that doesn't happen again.
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