Chainsaw Repair
Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Husqvarna => Topic started by: Gregg MacPherson on February 22, 2014, 05:45:18 pm
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I just bought a 254SE to either fix or use for parts for my 154. The 254 has some cylinder scoring and maybe some galling or metal transfer from the piston. I'd like to try dressing that with wet and dry or emry paper, but it's hard to know without experience whether the cylinder damage is too bad.
It's really hard to usefully photograph. There is some scoring and galling or metal transfer above the exhaust port. The scatches don't look too deep. Just below the exhaust port there is some heavier looking scoring and galling. Just below the main inlet port there are a couple of deep, short scratches. If all this is dressed of level with sand paper and my compression is good, are we OK, even if some scratches remain, below the finished level?
To dress the cylinder I was going to wrap the paper around a tube slightly smaller than the cylinder.
I don't know how this damage happened. Running too lean, not enough oil in the fuel? Can the bearings or seals be damaged at the same time, or does the piston, cylinder damage stop things before that happens.
Cheers,
Gregg.
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Look here for how one builder does it:
http://chainsawrepair.createaforum.com/ported-saws/how-to-remove-aluminum-transfer-without-acid/
His technique works quite well! The scotch brite trick really works like a charm!
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Thanks. That was an interesting watch. Seems like it's the hard layer of chrome is what makes this work.
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You are correct, sir!
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Keep in mind that if the chrome is compromised down to the base metal the acid isn't a good idea. Use a Dremel or like with a rubberized diamond wheel (fine) to remove the aluminum. Works well without chewing up the chrome if done with care
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Keep in mind that if the chrome is compromised down to the base metal the acid isn't a good idea. Use a Dremel or like with a rubberized diamond wheel (fine) to remove the aluminum. Works well without chewing up the chrome if done with care
How about using craytex.
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I've always used Craytex wheels...
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Finding the reason for the scorching is very important. There is little point in fixing the top end, unless what caused the damage is eliminated!
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Finding the reason for the scorching is very important. There is little point in fixing the top end, unless what caused the damage is eliminated!
In the case of the 254 I just got, the owner says he got the saw like that, which may be true. So I don't have any given history. How can one find out?
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Well you probably should get used to removing the muffler before disassembling the saw to see what cylinder/piston damage there is. Then do a pressure/vacuum test. You can use some sort of soap and water mix to spray onto the seals, around the crankcase and everywhere else the case could leak, including the cylinder base and decomp valve as well as the input tract. When you put pressure into the saw the soapy water will bubble up around the leaking air.
Finding the reason for the scorching is very important. There is little point in fixing the top end, unless what caused the damage is eliminated!
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FWIW Scotch-brite and kerosine is probabley the safest method to clean up a cylinder .It's just takes a little more elbow grease .
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Well you probably should get used to removing the muffler before disassembling the saw to see what cylinder/piston damage there is. Then do a pressure/vacuum test. You can use some sort of soap and water mix to spray onto the seals, around the crankcase and everywhere else the case could leak, including the cylinder base and decomp valve as well as the input tract. When you put pressure into the saw the soapy water will bubble up around the leaking air.
Yes, but it is a pity that he likely pulled the top end off before he did that.
Anyway it could also be about leaking fuel hoses, or a non-functional impulse - could also be a faulty carb.
Of course the most likely reasons are bad or streight gas, or too lean carb settings - but if he doesn't know for sure that it was, all the options need to be investigated.
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All these must be investigated before the declaration of being finished
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You guys are hard core.
Initially, after spending a miserable winter without my own saw (read as having to use someone else's Craftsman and cut wood for someone elses fire so I could cut wood for myself) I wanted to fix my Husky 154. As a reaction, I recently bought a Stihl 021 (yes a weekend saw for girls) as an emergency backup, but good for some light, high pruning around home. But the romanticism of fixing the old Husky 154 was strong. It was surprisingly easy to fix, even if I did have to remove the oil pump 5 times. It's now good to go (fingers crossed), though I still can't sign off properly on the fuel system. The 254 may just be for parts, but may be a fun exercise to fix. Parts from the States are cheap.
So if there are forensic ways of finding out what happened to the 254 and what the dammage may really be, I am interested. But if it gets too scary, this saw will become parts for the 154.
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There's nothing wrong with a 021 as far as that size chainsaw goes. I have a 025 and a MS 250
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Get after it Gregg! Nothing better than making a saw that doesn't work, run again! You will be amazed at the satisfaction you get from it. When it runs again, it will become your favorite saw, no chit you will love it! It will give you the know-how, confidence and inspiration to do it again and again!
The members here are not 'hard core' we are here to help!
Don't turn a great old saw into parts!
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.....The members here are not 'hard core' we are here to help!.....
Hard core just meaning seriously into it...
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No problem, Gregg! Lets' get the saw running again! What ever help you need, we will be there!
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Just a few things to look at, even though you removed the cylinder;
You could try to turn the H and L screws of the carb in until they seat lightly, and carefully notice how much you can turn them. That will at least tell us how the carb settings were when you recieved the saw.
The fuel lines needs to be bent sharply, to see if there are cracks in them - and it likely is best to replace them anyway.
Also look closely for cracks in the intake between the carb and the cylinder.
Were the cylinder bolts tight or loose when you removed the cylinder? If rather loose, air may have leaked at the cylinder base.
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I was going to mention that I had checked the carb H,L settings. They were about right at the standard presets from the manual when you tune the carb from scratch. But I don't have reason to assume that they haven't been otherwise. I supose if the high was screwed too tight it might have looked a likely cause, running lean and hot.
The cylinder bolts felt very tight to me. I had a torque wrench there but I didn't measure that.
I can check the fuel lines. Can one apply a little air pressure and listen? Didn't get my stethescope kit yet to make a pressure test kit.
Joining a firewood posse next weekend so the 154 will get a serious workout. I'll see how that goes.
Thanks for the help you chaps. (in the colonies chaps are people not a pair of leggings)
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Gregg, you can use air on fuel lines but, given the age of the saw it is probably better to just replace them. Most often they go to chit right where they exit the fuel tank. Everything that Nikko suggested checking is also a very good idea to do on all saws no matter if you suspect a problem or not. The 254 is one of Nikko's favorite saws, so on this particular model of Husqvarna (or any other for that matter) he would not steer you wrong.
So after the firewood posse, are you fellows headed off for a pub crawl?
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......
So after the firewood posse, are you fellows headed off for a pub crawl?
Of course they are, but hopefully not before they do the cutting..... :-\
Yes Gregg, I know very well what "chaps" means in OZ, and I suspect most others do as well. ;D
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Well here in Wyoming chaps is what we wear while riding our horses. ;D ;D
But if I recall correctly I saw a movie once where one guy called another, Hey ole chap.
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Pub crawl? Nah, we'll probably settle down for a quiet meditation, then some nice vegetarian food. Two saws will be cutting for five fires. It'll take two or three days before it's all extracted, cut, split and shifted. The 154 will get a lot more work than it normally would.
OZ vs New Zealand. That's a bit like mistaking Canadians vs Americans. It's always been a joke down here that Americans think NZ is attached to Australia. There is a friendly but fierce rivalry between Kiwis and Aussis. The word "Chap" in NZ is sometimes used straight, but often with some mild humour, a comment on Englishness.
Back to saws.
I did look in the 254 exhaust port first. Seeing the scratches on the piston, I went ahead a pulled the cylinder. I hadn't heard or thought of pressure testing for leaks at that stage. On that point, what's the easiest way to set up that pressure test? The input and the plugs.
How does one assess the bearings without splitting the crank case? The gudgen pin rollers I haven't got super clean yet for a look, but my finger nail may feel some pits. The big end bearings I can see the ends of the rollers and they are rolling in their cages OK and look clean. I don't know if this usefully tells anything about big end wear, but the side to side play at the top of the con rod is about 1.5mm.
Cheers,
Gregg.
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OK, the easiest way to block off the engine for pressure testing is a bicycle inner tube. You cut two strips off the tube just wide enough to fit between the exhaust and intake bolts. You then tighten up the bolts just enough to compress the rubber and create a seal. You can buy or make from an old spark plug something to seal off the cylinder and leave a nipple for the pump hose. You get a pump connect it to a hose connect the hose to a pressure meter and then run a piece of rubber tubing from the meter to your spark plug device. Pump 80kPa into the motor, if at the end of 30 seconds the pressure is above 60kPa you are good to go!
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OK, the easiest way to block off the engine for pressure testing is a bicycle inner tube........
Ta mate (translates as "thanks man")
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Nada, translates to 'it was nothing' in Portuguese.
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Nada, translates to 'it was nothing' in Portuguese.
Try this one...
http://www.translatebritish.com/index.php
Means the same in NZ slang.
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On the issue of how this happened to the saw. I was randomly looking around the forum and found thois by KRL.."..If there is no mix oil left in the can after the gas evaporates off then chances are that the saw was fed improper fuel..". I then realized that this was one thing I could have done. Not to assume that the gas in the tank was the same gas as when it was damaged, but if the gas was low on oil or without oil then that is a probable cause.
Without thinking through any such things, on buying the saw I washed the gas tank and tried to start it with good fresh fuel. I think I will never buy another saw without pulling the mufler first.
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Axiom #1
"I will never buy another saw without pulling the muffler first."
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Axiom #1
"I will never buy another saw without pulling the muffler first."
I like that.
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Axiom #1
"I will never buy another saw without pulling the muffler first."
How many axioms are there?
I know I missed two when I bought that saw. I could have pulled the mufler and I should have pulled the clutch cover and looked at the chain brake, sprocket, bar and chain, to get some idea of how it had been treated. One thing that mislead me was the seller telling me that the chain wasn't a match for the saw. It hadn't been run like that so why look.... When I got home I found what looked like the wrong clutch cover, the wrong bar (14" 3/8LP as per my Stihl 021) and an 18" 0.325"/0.058" chain. At least the rim sprocket was 0.325" pitch.
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Your doing fine Gregg. Just as you have figured out by pulling the muffler, you will discover other things to look out for also. I think pulling the clutch cover is not a bad idea too.
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Gregg, the 'kitty food can' method is only a very rough indication. I have a 100ml test tube (100ml because it makes the calculations easy). I put 100ml of fuel in it and let it evaporate, if there is 2ml of oil left in the tube then the mix was at 50:1, 2.5ml=40:1, 3.1ml=32:1,etc. While this is a more accurate method it is still only an indication depending on how long the fuel has been in the tank some may have evaporated throwing your measurement off. I have never had much luck letting the fuel stand in a closed tube and wait for the oil to separate from the fuel because the oil is designed to stay mixed with the fuel.
Have a look here:
http://chainsawrepair.createaforum.com/ported-saws/piston-failure-analysis/
Fuel mix problems are pretty evident by looking at the piston no matter what the above test shows. If I go to look at a saw I take a very basic small set of tools with me, just those tools including a small flashlight (torch in Brit) that will allow me to get the muffler off and have a look inside. And +1 on 660Magnum's axiom #1!
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When you go to look at a chainsaw, besides Axiom #1, people take into consideration the overall appearance of the chainsaw.
As well I want to see the guy start it and hear it run . . .
I also want to pull on the cord. With this, I'm getting an idea of the compression and the smoothness of the bearings.
You can usually feel for bearing sloppiness and roughness on the clutch side. Often, running the chain too tight will ruin the clutch side first?
If the bearing is bad, the seal is bad too.
You can see evidence of the chain having jumped off continually which makes you wonder about other problems and the characteristics of the operator?
A commercial saw run by none owners with a lot of time on it is usually pretty dog eared. This will be very evident to you.
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So after the firewood posse, are you fellows headed off for a pub crawl?
Well, we had a really good session with the firewood posse. The 154 with a carefully sharpened chain cut like a champ. Some 2-1/2' wattle logs, I think they were wattle, landowner said so, very dense, fine grained, white colour, very straight, like from a plantation, a couple of shakes or visible stress lines near the centre that split well with the ax. Anyway the Husky 154 (18") had hot restart problems, so I grabbed the 14" Stihl 021 and with a new chain it cut these logs quite well also.
On the first night I tightened the carb mounting screws, which improved the hot starting problem, but I need to give the fuel system a full look over. I think the carb mounting screws might have been left a little less than tight because I was scared of stripping the threads when I assembled the saw after a jamed piston a couple of years ago.
I will have to find time to play some more.
You guys were a lot of fun.
Thanks again, and cherio.
(see if you can figuire out what cherio means, though I s'pose Google etc make it pretty easy)
Gregg.
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Well "cherios" are little round cereal rings that look like little inner tubes made from oats .They float on milk but get very soggy after a while and sink ,if that means anything . ;D