Husky 3120 wont rev - stalls - did a carb clean up and no difference ??!

twoodward15 · September 14, 2005, 11:40:05 AM

It's time to ease up on the compressed air. Just use a rag to dry parts. No need to use your air compressor. It's kind of like cleaning your ears with 125 psi. Not a real smart thing to do. THese small carbs aren't as tough as the old quadra-bog on the 79 chevy truck. Just squirt on the carb cleaner and gently clean the part with a rag. Leave the air tank empty.

chainsaw_louie · September 14, 2005, 12:30:28 PM

I'll try to send a picture of the little white plastic plug that flew out of the carb. I hope it was the piece that actually came from the carb and not something else on the garage floor that I mistook for the right piece! But I'll get a picture up here and it will be clearer.

I just got a response to the email I sent to Madsens and their tech guy says:

"Hello,
Pull your muffler off and look for damage to the front of the piston.
It sounds like a seizure damaged piston. " He says its common for this to happen to milling saws (thats me).

Thats pretty depressing to think about....actually after reading the article on the Madsens website about EPA saws, its seems like a blown saw waiting to happen which is real depressing. I thought I bought something that would last ..... anybody hear of saw insurance?

So I'll cross my fingers and have a look at the front of the piston. Wish me luck....

Tim

Have a read here http://www.madsens1.com/epa.htm

woodbowl · September 14, 2005, 01:30:11 PM

Quote from: chainsaw_louie on September 14, 2005, 12:30:28 PM
..... anybody hear of saw insurance?

Yea............I saw insurance availible when I got my sawmill. It cost too much so I decided not to get any. ;D

chainsaw_louie · September 15, 2005, 12:15:12 AM

I got the message about not using the compressed air... wont do that again.

Tonight I took off the muffler and checked for scoring and melting of the pistion like the tech guy at Madsens thought was the most probably cause of the 'wont rev' trouble. Well, there are some black marks on the piston by the exhaust port side, but it was not long scoring/scratches and definately not melting of pistion top or piston rings. From what I could see the piston looks in pretty good shape and ditto for the rings. I am going to say then that that is NOT the cause. Unfortunately the exhaust gasket came off in 2 pieces and my order from Madsens already left. I gotta find a good local shop here in NYS.

Hey, I took some high res digital pictures of the piston, and the little plastic carb piece but I kept getting errors on the upload screen, even after I shrank the image quality down to 27KB it still complained "Pixel allowance exceeded". Not sure what thats about.

For now, my next step is to wait for the carb kit and fuel line and see what that does. If nothing else, I know a heck of a lot more about this saw and how to care for it than when I started digging into this problem.

Tim

chainsaw_louie · September 15, 2005, 12:19:22 PM

I was not able to upload the pictures to this site but I got the instructions and will post them later.

I did send the pictures to Madsens and they said

"Hello,
You definitely have a seizure damaged piston. You will need a new piston and possibly cylinder if it can not be honed clean. Sorry for the bad news. "

Thats a rather severe appraisal and I dont get it how a saw that will rev with gas fed through the carb needs to have the piston replaced but I dont have the experience.

ehp · September 15, 2005, 12:48:48 PM

Without seeing it forsure I would say you are correct, you donot need a jug and piston because of what you did, it is not a hard thing to fix once it is in good hands, where are you so I can tell you if I can where to go for help?

floyd · September 15, 2005, 02:53:00 PM

anyone ask you about the diaphragm in carb?

woodbowl · September 15, 2005, 09:35:42 PM

Quote from: chainsaw_louie on September 15, 2005, 12:19:22 PM

"Hello,
You definitely have a seizure damaged piston. You will need a new piston and possibly cylinder if it can not be honed clean. Sorry for the bad news. "

Thats a rather severe appraisal and I dont get it how a saw that will rev with gas fed through the carb needs to have the piston replaced but I dont have the experience.

I question that as well Tim. Put in a carb kit. That is the standard practice anyway. It's one of the first things the shop would do. I still don't know if your fuel line sucks air and fuel filter is clogged. Actually, those things are first. It ain't gettin' gas that's for sure, scored piston or not!

CHARLIE · September 16, 2005, 01:30:58 AM

I have a Craftsman chainsaw I use to cut bowl blanks for my woodturning. It got so it would start but not run but about 10 seconds. At the time I had a neighbor that was a great backyard mechanic. He noticed airbubbles in the fuel line. The fuel line from the tank to the carb looked good, but we found it was cracked inside the tank. The small engine repair guy where I went to buy a new fuel line said that the fuel will harden them and they crack. As soon as I put in a new fuel line it ran perfect. I'm betting your fuel line is cracked inside the fuel tank. By the way, I know the Craftsman is pretty light duty saw but it sure has been a good one and done everything I need it for.

chainsaw_louie · September 17, 2005, 12:42:37 AM

Phew, now I think I got some pictures uploaded. First time thru the pictures took too much memory, then they had too many pixels, took muffler off again to re-shoot with low res mode, then install software to crop pics down to 30kb and finally they uploaded. Soooo here they are....

This is that mystery part that flew out of the carb while cleaning it with compressed air (which I will not do again). Its not the welch plug. Any ideas

And this is a blurry shot of the piston which was said to be seizure damaged. Is this a piston that needs replacing or is it pretty common to see carbon build up on the exhaust side of pistons like in the pic below?

I am getting real good at taking apart and re-assemblying the carb, muffler etc. Nothing like practice to learn something. I now see that I waited way too long to put a wrench to this saw. I figured it was rocket science and better leave well enough alone but tightening up the muffler, cleaning the carb etc is no big deal if you are clean and careful.

I got a suspicion what the problem might be but I'm scared to mention it cause if I am right you fellas would really kick my butt. Does it say anywhere in the forum rules that we got to fess up everything?

OK, well if you say so, heres what I am thinking....when I 'changed the gas' , I may have had water in the mix can that I put the new fuel in and water got into the saw. Cause when I poured the tank dry into a clear plastic container, I saw some water in the bottom. Tonight I cleaned the tank dry. I totally emptied the gas can and went and got a gallon of 93 octane. Tomorrow, I'll put in that clean fuel in and give it a try. I'll let you know.

Tim

woodbowl · September 17, 2005, 06:28:05 AM

Not to worry Tim. The fessin' up thread has already been started by da Boss his self. Fill free to unload yer' guilt, brain strains ect. Everybody's done it at one time or another, they just don't admit it. Here's the thread.

https://forestryforum.com/board/index.php?topic=12725.0

Kevin · September 17, 2005, 09:42:52 AM

Here's the G7 ...

G7 link

chainsaw_louie · September 17, 2005, 09:55:00 PM

Well I wish I made it to the "fessin up " site - by that I mean that I wish the problem was water in the fuel and changing it out solved the problem. But the saw is still not reving or running right with with good fuel and no water. Still waiting for the carb kit.

Thanks for that link to Walbro schematics, thats a great resource, got it bookmarked in my 'chainsaw tech' folder I can see there is a little plug in the diagram - got to view it on a better monitor to be sure it is what I think.

chainsaw_louie · September 19, 2005, 10:51:52 PM

Here's an update after some more investigation, while waiting for the new parts to arrive.

Someone suggested that the fuel cap vent might be clogged but these caps don't have a vent hole. So the next logical thing to check is the tank vent itself. I figured out how to lower the fuel tank/handle assembly and pull out the fuel tank vent. My assumption here is that the vent should allow a ONE Way flow of air. I tried blowing through it, in the towards-tank direction and there was a LOT of resistance - this resistance may be normal but it seems to me that its too much and it may be holding back the flow of fuel.

I have noticed that recently, the saw leaked gas from around the tank cap. I just figured that the O-ring around the cap was bad and just screwed the cap down tighter. But this leaking may have been due to a clogged tank vent, or the cap is bad. I guess I could try loosening the fuel tank cap and trying to start it. That should pretty much answer the question of tank ventilation causing the fuel starving/stalling situation.

Tim

twoodward15 · September 20, 2005, 07:19:02 AM

Definately. Fill the tank half way and leave the cap off totally if you have to.

chainsaw_louie · September 22, 2005, 11:22:41 PM

Well folks, I got Good News! The saw started and ran today! Hurrah! To celebrate the occasion, I cut up a bunch of firewood. It idled and revved just fine.

The last thing I did to it was remove fuel tank vent and blew it out with compressed air. My thought was that it was clogged but the air blasted it free and cleared whatever obstruction there was. When I got the NEW vent, it too had a lot of resistance so I put the original one back in figuring resistance is normal and the saw started up with a few pulls. After some turns of the low speed jet and then set the Idle and it was ready to go.

I never put in the carb kit, but will when it arrives, just cause after 2 years it cant hurt. It was back ordered.

Never replaced the fuel line - did you know they charge $18 for the Husky fuel line Holy Mackerel! I got one on order for the future

Thanks for all the help to figure this out. I sure learned a lot about how to take care of this machine. Would there be any interest in posting a flow chart of troubleshooting steps to get a dead saw running? I could put together a first draft and the others people could suggest additional steps. It just seems like it would have been an unfortunate waste of money if I had of had the piston and cylinder replaced as someone outside the forum suggested to me. Am I the only chainsaw dummy here?

Anybody knows where to get Husky parts in the NY NJ CT area, which has a good stock of parts?

Tim
aka chainsaw_louie

ehp · September 22, 2005, 11:56:13 PM

no it is done everyday . Just glad you got it to work,

woodbowl · September 23, 2005, 09:26:30 AM

Glad you got er going. When that kit comes in, if it's still running good, personally I wouldn't mess with it. If it ain't broke, don't fix it............One thing still puzzels me.

Quote from: chainsaw_louie on September 22, 2005, 11:22:41 PM

The last thing I did to it was remove fuel tank vent and blew it out with compressed air. My thought was that it was clogged but the air blasted it free and cleared whatever obstruction there was. When I got the NEW vent, it too had a lot of resistance so I put the original one back in figuring resistance is normal and the saw started up with a few pulls.

Never replaced the fuel line

You never did say if it ran good with a loose gas tank cap. That would have vented the tank. If it didn't...............I think something quirky is going on! And it happens. The saw is running fine. The saw is not running fine. Those are the type of problems that drives people crazy. If it was really crud in the carb, hopefully it kept going. Put that kit on the shelf for later and run the stew out of it!

Quote from: chainsaw_louie on September 22, 2005, 11:22:41 PM
Am I the only chainsaw dummy here?

No.............the rest of us just don't have the nerve to admit it. ;D ;D ;D

chainsaw_louie · September 23, 2005, 10:10:21 PM

At this point I recall that I did not get a good test with a loose gas cap, . That was a bit of a challenge for me due in part to the position of the tank - and not wanting to spill the gas. My cap O-ring is bad and will leak a lot if left loose. This test would have been an easy way to verify a vacuum pressure problem. I'll be sure to remember it for the future. Thanks!

chainsaw_louie · September 27, 2005, 11:46:36 PM

Hey Fellas,

I came across this parts diagram/book on the Husqvarna site, they got these for all their machines. Its a great help, it has the complete schematic of the saw including clutch, as well as all the parts to the Walbro carb - including that mysterious white plug, I was talking about...

I wish I had seen this diagram when I got the 3120xp

http://weborder.husqvarna.com/order_static/doc/usa/2003/I03000/I0301155.pdf

To find any Husky saw part diagram, navigate to www.husqvarna.com
Click Support
enter Product= chainsaws
enter Category= parts
enter Keywords = 3120xp etc
then hit seearch and you will see a link for Illustrated Parts List (IPL), thats the doc

-CSL