Hi all,
I'm looking for help with a Husqvarna 346xp rebuild. I replaced the rubber boot in the manifold (which was broken), the gasket and the cylinder and piston (both scored). After all that I did a pressure test with no leaks so I went ahead and put her back together. Then came the compression test and she only scored a meager 100psi.
Would anyone have a suggestion as to where to go from here?
As well as I like my 2 346's I have read that they can be upgraded to be even better with a rebuild, I forget which jug and piston to use though.
I would nearly bet if you still have 100 pounds compression, that your jug can be cleaned up though, so new piston and rings, may very well be all you need.
Are the p&c new? Are they OEM or aftermarket? Is the cylinder gasket correct thickness for your saw? Are you certain the compression gauge is accurate?
The new piston, ring and cylinder are all OEM and the gasket is the correct one. The pressure gauge is brand new (Draper). It read 60 psi before I replaced the impulse line nipple, then it only improved to 100psi. There were no air leaks when I pressure tested with a vac pump.
For a bit of back story: I loaned the saw to my bro-in-law who I suspect ran it on straight petrol (or near enough to it). The electrode on the spark plug was snow white when I got it back.
I've owned and used chainsaws both privately and professionally for fifteen years but this is the first time that I took one apart to this extent myself. So my knowledge of all the little things that can go wrong is little enough.
I mis read your post and didn't realize you had put a new jug and piston already. Does it crank and run, it could be your gauge is off. Another question is is the cylinder dry, or are you getting gas in it.
You may need to do a squish test, it is possible you need to delete the base gasket, others more familiar with that will surely be along.
Is your compression test before or after the saw has been broken it? I'm sure the PSI rating will go up considerably after the rings have seated with some usage and a bit of carbon fills in the ring gaps and the top of the piston to some extent..
All I know for sure is, I've never seen a happy ending to a loaned chainsaw story on here👎
If 100psi is correct, than you got problems somewhere that's for sure. I've put on a lot of these OEM kits, and usually get compression of 150 lbs with gasket. At this point, I would do a pressure & vac test. Maybe plug the decompression valve as well. Keep us all informed.
I forgot you did a press. test. I would also check with another compression tester as well. Your squish ideally is no less than 18-20 thousands. But it will be more than that I'm sure with OEM gasket, maybe 30-40. Check that with thin wire solder. There are 2 different OEM 346 cylinders and piston bores as well. You may not know this. The OE (old edition) 42mm, and the NE (new edition) 44.3mm. Make sure they are not mix-matched. I say that because, I have gotton a OEM NE P/C kit that had a OE piston included. That doesn't make for very good compression. If you can't find the problem, tear it down again and measure everything.
Quote from: barbender on March 22, 2018, 08:51:02 PM
All I know for sure is, I've never seen a happy ending to a loaned chainsaw story on here👎
I should get one of my 346's back this week, I loaned it to my kids and it has cut every stick they have heated their house with the last two winters, so am wondering how it will be. I know it still at least runs, cuz they ain't froze yet.
Quote from: starmac on March 22, 2018, 11:11:30 PM
Quote from: barbender on March 22, 2018, 08:51:02 PM
All I know for sure is, I've never seen a happy ending to a loaned chainsaw story on here👎
I should get one of my 346's back this week, I loaned it to my kids and it has cut every stick they have heated their house with the last two winters, so am wondering how it will be. I know it still at least runs, cuz they ain't froze yet.
There ya go! Lol We need to take care of our kids don't we! I think I'd have to give'em 1 of my rough old 350's - just in case! Neither burns wood yet, but 1 is thinking about it more.
Funny you should say that, when they picked it up, I was going to give them my 455 which I had had riding in the back of the pickup for a couple of months. I had been using it for a mill saw, and it starts easy and run perfect, but it had been raining for nearly two weeks, so I had not started it. It would start right up, but then die as son as you touched the throttle, I tinkered with it a few minutes then just gave them the 346 with a stearn warning.
Hi, I haven't gotten back to the saw since. Spent a couple of hours yesterday tidying my workshop while looking for my calipers which I didn't yet find. Thanks for the suggestions so far. Hopefully the problem will turn out to be one of them.
Hi all. I Couldn't find a digital calipers (either my own or in two local hardware shops) but decided to go ahead and do the squish test anyway just for the craic. I checked the decompression valve with a little soapy water and it's air-tight when closed. Anyway, there is literally NO squish on the solder. I actually think I could have used my pinkie finger for the test! What the heck? I used an OEM piston and cylinder kit with the (apparently correct) gasket. Maybe I need to machine down the deck?
Here's a link to the kit I bought https://www.eurosmallengineparts.ie/husqvarna-346xp-350-351-353-cylinder--piston-45mm-nikasil
And the gasket: https://www.eurosmallengineparts.ie/husqvarna-346-350-351-353-xp-base-gasket?search=5038944-01
EDIT: As anyone who followed those links may have worked out, the cylinder and piston kit are not OEM but are Hyway....which well, may be part of the problem?
I just saw your edit. Yes, that is not true OEM. That's the Hyway 45mm big bore kit. Tell you what I would do. Simply delete the base gasket and use 1184-94 gasket sealer, or as some call 3-bond. This will raise your compression some, but may not be enough. Got nothing to lose at this point. Or you could go buy a "true" OEM kit for around 120-130 $. That should put your troubles behind you. To help you out alittle more, I would do some trading with you for an OEM kit I have. I have 5-6, so no big deal. Your call.
Quote from: wild262 on March 27, 2018, 10:20:54 AM
I just saw your edit. Yes, that is not true OEM. That's the Hyway 45mm big bore kit. Tell you what I would do. Simply delete the base gasket and use 1184-94 gasket sealer, or as some call 3-bond. This will raise your compression some, but may not be enough. Got nothing to lose at this point. Or you could go buy a "true" OEM kit for around 120-130 $. That should put your troubles behind you. To help you out alittle more, I would do some trading with you for an OEM kit I have. I have 5-6, so no big deal. Your call.
Thanks for the suggestion and offer. I'm guessing that you're in The States? I'm on the other side of the puddle in Ireland so I reckon shipping could be pretty expensive in terms of doing a trade.
I'll try without the gasket for the moment and see how that does. I have some Indian head gasket shellac. Would that do the trick?
Its worth a try. Big things are to be certin the jug base and the block face are clean with no step at the parting line... And DO NOT get antsy to crank it over just for a test feel. Let the stuff really cure overnight.
No I hadn't really looked at your location until after you told me. Just assumed you were here in the US. You really ought to get that 1184 or another would be Dirko. Dirko is what Stihl uses. I just don't like to use it on Huskys because of the color being red for coverage reasons. As far as the Indian head, I can't say but I doubt it will work. The 2 products above are proven to work for sure. That's the only 2 I would use. If you got anyone with a milling machine you could take off enough material from the bottom and still use your gasket for the squish of your choosing. 20 thou. would be perfect. That's the way I would go hands down if it were mine. With the 1184/dirko you might get 120-130 lbs, if your lucky.
Quote from: barbender on March 22, 2018, 08:51:02 PM
All I know for sure is, I've never seen a happy ending to a loaned chainsaw story on here👎
Never a lender or a borrower be. all my life I have lost out to friends on loaned items as I cherish everything I buy, simply because I went out to earn it to buy it because I needed or wanted it at the time, so it offends me when a friend would dare ask if they can borrow my tools or electrical items.
I will do jobs for them for nothing before I will lend out anything now to anyone.
I have borrowed in my younger days and paid the price of marking it or damaging it and having to fork out for a brand new item.
Seems I'm the fool for replacing the broken or marked item as no-one I have ever met will do this for me and certainly not in present day society.
Which is why I cannot afford to lend things nowadays.
Thanks a lot for the suggestions. Unfortunately an OEM cylinder and piston kit seems to be difficult to acquire over here. The best deal I could find online is for £270 from a UK website. I went down to my local Husqy dealership and the guy there gave me a talk about how he had to wait for weeks to receive a single shock absorber spring and shared with me his suspicion that they weren't paying their bills. Well I don't know anything about that.
Anyway, the customs charges for having an OEM kit imported from the USA are usually prohibitive, but may still work out cheaper. But could anybody help me understand why a replacement part, spurious though it may be, won't fit the purpose that it was supposedly designed for. Are there other brands apart from Hyway which would have the same dimensions as an OEM cylinder?
My other option is to have someone machine down the deck a bit. It this a difficult process? Should I let a person with no specific experience with chainsaws carry this out?
As I said in a post or 2 back, I would just work with what you have. Find a machine shop to mill down your head. First thing, with cyl. and head gasket in place, measure your squish again in several places. Say you have 45 thousands average. To get to an ideal 20, you would need 25 thousands milled off. This will get your compression were it needs to be. This way you can use your OEM gasket and no 1184 would be needed if the gasket is good. Otherwise the gasket delete and 1184 is needed, And I doubt your compression would be much better than 120-125lbs. Would still run, but not well, and NOT like before. It would however "get you by". :) Maybe someone out there has a better answer. Keep us posted.
I contacted the company from which I bought the Hyway kit. He seemed baffled that the compression was 100psi and thinks there might be something else wrong with the saw. I don't know what that might be though. I think I'll try to find a shop that will mill it down a little and failing that this guy quoted me around €200 for a new OEM kit.
There is nothing wrong with keeping the current jug.
If it has a base step you need to make a mandrel and chuck that in a lathe, then push the jug onto the mandrel with a tailstock center and turn the material off with a lathe bit. Iv made dowels from wood, then shot a screw through a port into thr dowel so it cant spin. A light tap fit is best here and its okay to shim the dowel OD up with some tape to get there. Just make light cuts.
If the base is flat you can belt sand or hand scrub sand the meat off the base. Measuring the 4 corners as you go until you whittle down to the desired thickness evenly. Be sure youve got a glass surface to check flatness with. If you were talented enough you could rough it down with a hand file then flat sand.
I use a ceramic tile or sheet of glass with sand paper over it for a sanding surface. If you put water in a paint pan or tub then soak the sheet, it will self adhere to the glass and stay put. As it loads up with aluminum, rinse again.
If you end up taking off a ton, it may lose rpm up top. Raise the echaust ports and transfers a little to recover this. The upper transfers also benefit from being "pointed" toward the intake side to evacuate the spent gasses and not lose the fresh charge out the exhaust port.
Additionally, you dont want ultra smooth finish, thats for metal gaskets. Paper and sealant benefit from some tooth. Its quantified in roughness area or RA, and is what a profilemeter measures.
These peaks and valleys create higher pounds per square inch of pressure between the surfaces. When i lathe turn them i leave some cutter mark. When i hand surface i leave some swirly score. If i was taking down 20 thou id start at like 60 grit and finish maybe 200.
Thanks a lot for those suggestions Mike Belben. I wish I could say that I was even at that stage both generally in terms of my own capabilities and specifically in relation to this project which has taken a new turn into the unknown as far as I'm concerned.
I tried starting it up just to see how she'd run and the results were not very comforting. It took a lot of pulling to get her fired up (normally she'd start after three pulls with the choke open followed by one with it closed off). Once she started I opened up the throttle fully and she'd run high for a few seconds before dying immediately when I release the throttle. Little bit of smoke coming from the muffler end to that didn't strike me as your normal exhaust fumes.
I'm stumped, but then again, the reason I embarked on this project is to learn about how the saw worked and how to fix it. So I can only look at this as an opportunity to learn more. :)
It needs a tune before you can knock it.
Crank up the LA screw and get it running fast. Adjust the L screw until you find the highest idle speed then turn LA back down until chain stops walking/shuddering.
Now adjust the H screw so that at WOT no load there is a bit of a raspy burble called 4 stroking, this is a rich condition. You have nailed the H setting when dogging into the wood makes that burble suddenly shift to a crisp clean dirtbike sound, called 2 stroking. Lift off, raspy. Dog in, sharp.
You got this Dan, piece of cake.
Ps- i start with both screws about 1.5 turns out. Very gently crank the H/L all the way in until the seat. I mean very gentle or you can snap the tips inside on some.
The chain is running fast at idle no matter what adjustments I make. The air filter and carb are both clean (new carb kit installed). ???
Ok panic averted. I adjusted the carb and I have her running ok. The chain isn't creeping on idle and she's no longer cutting out. She does sound a bit rough, even raspy, at full throttle. I'm not convinced she's tuned 100% so I reckon it might be wise to take her to someone with a bit more knowledge than me. Or would it be advisable to invest in a tachometer?
If WOT sounds like its fouled up and held back from really ripping, its very rich. To be sure youre describing a rich and not lean.. Turn H way out until the rpm declines and note is very lazy and cackled. Tune your ear to it. Then turn the H screw in (cw) until it cleans up almost entirely.
Like i said earlier you want that light raspy cackle at WOT in the air, but when you wrench down into the wood with a full bar, for the tone to change to sharp as if you flipped a pressure switch that changed modes.
Sometimes you have to tweak the L screw a bit after a major H change. A good indication is if top end is good but its hard to get the saw to come off idle. It should snap right up from idle to WOT when all is right. This is a skill thatll take you a while so dont stress about it. Do the best you can.
Hi all, I just received an oem kit and a tachometer. So I took the saw apart again and a few things popped up which I hope someone on here can help with. for a start I want to make 100% sure that I'm attaching the hose/lines to the right places. What I had done was attach the fuel line to the carburettor (I worked out that much myself :-). I attached the tank vent line to a little plastic nipple on the air intake (a pure guess). Then I attached the line running from the primer bulb to a little plastic nipple next to the fuel vent which seems to open into the fuel tank. I looked everywhere online to find a diagram of this but the majority of the 346xps out there don't seem to have primer bulbs so I had to resort to guesswork/ trial and error. One error which occurred was a kink in this primer line so the fuel couldn't return to the tank from the bulb.
(https://forestryforum.com/gallery/albums/userpics/49279/rsz_dsc_0009~0.jpg?easyrotate_cache=1523457429)
I noticed that there was a vinyl ring/ spacer between the clutch drum and the sprocket. It looks a little worse for where and I can't find any reference to it on any parts diagram or youtube videos which deal with this saw. Should I just leave it?
(https://forestryforum.com/gallery/albums/userpics/49279/rsz_1dsc_0010~0.jpg?easyrotate_cache=1523457425)
Finally, I noticed worryingly that the head of the brand new piston I put in is badly pock marked around the edge, as is the top of the cylinder itself. What on earth could have caused that. No scoring or damage to the piston or cylinder otherwise.
(https://forestryforum.com/gallery/albums/userpics/49279/rsz_dsc_0007~0.jpg?easyrotate_cache=1523457425)
The dents ontop the piston are from debris smacking the head. Look inside the jug to verify.
The little nipple off the intake is the impulse line, crankcase pressure is applied to the silk diaphragm in the carb and it flutters, acting as a fuel pump and operating the float needle. Im not certain how it would be routed with a primer but impulses go to the carb.
The vent hose may just go to a clip holster of some sort, look around
I made a mistake. I forgot to put the needle bearing in when mounting the piston. That's probably the culprit?!
:embarassed: I'm getting there....slowly. Lucky for me the rod looks fine and I have a brand new oem cylinder ready to go.
You got lucky. ;) With all OEM, I would use the gasket if I were you. You still should achieve 150lbs compression. Don't use any sealer if you use the gasket. Really no need to.
The needle bearing is also why you had low compression.
Quote from: mike_belben on April 12, 2018, 11:31:31 PM
The needle bearing is also why you had low compression.
Bloody hell. Do you reckon the piston and cylinder are shot now?
Piston crown is fine but you havent shown the skirts or cylinder. Id be more concerned about the little end rod bores finish and roundness.
Just a few pics of the rod and cylinder. The rod looks OK to me anyway, although I think it has been fairly well established that I'm no expert!
(https://forestryforum.com/gallery/albums/userpics/49279/DSC_0021.JPG?easyrotate_cache=1523620718) (https://forestryforum.com/gallery/albums/userpics/49279/DSC_0018.JPG?easyrotate_cache=1523620739) (https://forestryforum.com/gallery/albums/userpics/49279/DSC_0025.JPG?easyrotate_cache=1523620770) (https://forestryforum.com/gallery/albums/userpics/49279/DSC_0017.JPG?easyrotate_cache=1523620784)
I went ahead and reassembled the saw. Passed a pressure test once I plugged the decomp.
Question: should I leave it plugged or reinsert the valve?
I got 150psi of compression then which I'm happy enough with. It's running pretty smooth now also.
I removed the vinyl spacer from the clutch but then the sprocket wheel was loose so I put it back. I still not sure about it, but I'm even less sure about a loose sprocket wheel. It might be a feature of this particular model. I bought it in 2008 or 9.
I'd like to thank everyone on here who contributed with instructive advice and encouragement.
smiley_beertoast
Quote from: Dantheforester on April 13, 2018, 03:43:33 PM
I went ahead and reassembled the saw. Passed a pressure test once I plugged the decomp.
Question: should I leave it plugged or reinsert the valve?
I got 150psi of compression then which I'm happy enough with. It's running pretty smooth now also.
I removed the vinyl spacer from the clutch but then the sprocket wheel was loose so I put it back. I still not sure about it, but I'm even less sure about a loose sprocket wheel. It might be a feature of this particular model. I bought it in 2008 or 9.
I'd like to thank everyone on here who contributed with instructive advice and encouragement.
smiley_beertoast
Good work guy. Sounds like its all good as far as cyl goes. I don't ever remember a vinyl spacer on the cutch sprocket on these. I will pull up a IPL and get back with you on that. Did you replace the tore cyl gasket or patch that area with sealant? And does this saw have the metal intake clamp? Can't see very good in the photo. I don't use the decomp's on my 346 builds unless the customer wants them. There not that hard to start unless you have shoulder problems and such. Tune it alittle rich till its broke in.
I noticed that there was a vinyl ring/ spacer between the clutch drum and the sprocket. It looks a little worse for where and I can't find any reference to it on any parts diagram or youtube videos which deal with this saw. Should I just leave it?
I cannot find any reference to the above vinyl spacer. I don't know what purpose this would serve. Maybe someone else here knows or can find info on it. It might be an update that was on the later saws. I have never seen one before, and I have built several NE's.
Parts tree doesn't show a plastic washer on any models 1999-01. Except that funky trio brake model.
Quote from: wild262 on April 13, 2018, 04:13:25 PMDid you replace the tore cyl gasket or patch that area with sealant? And does this saw have the metal intake clamp?
I did replace the gasket. It does indeed have that clamp (little devil).
I'll be taking off that "vinyl spacer". I reckon that it may have been a strand of bailing string that wrapped around the shaft and fused with the heat to create a pretty convincing washer.
Thanks again.