Plugged tank vent?

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Migratory Hippie Arbolist
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Howdy folks,

I have a problem with my Husky 359. I think it's a plugged tank vent but I wanted some confirmation from the experts before replacing it, because getting at the tank vent on this saw is a serious pain.

Symptoms: Saw runs fine for little while (~5-10 min) but then suddenly will no longer rev up from idle without dying. Feathering the trigger helps for a minute or so but eventually the saw dies. Opening the fuel tank produces the hissing sound of moving air, and then the saw runs find again for another few minutes. So now I am in the habit of stopping every couple minutes of cutting and opening the fuel cap and closing again in order to keep working smoothly.

It's really annoying, but the fuel tank vent is in a seriously inaccessible spot on this saw so I wanted to make sure I had diagnosed the problem correctly before taking off the carb and other stuff to replace it. I am pretty mechanically retarded so I'm always worried I'm going to mess something up when doing any kind of complicated repairs...
 
That is what my 394 was doing. It would run fine, as long as I kept it running, but would be a bear to start again. I got the hissing as well. I took the fuel line off and blew air through it. That seemed to do the trick, but unfortunately, the tank wasn't completely empty, and it sprayed fuel about twenty feet after I took the air of the line. So be forewarned.;)
 
If the tank vent is plugged, then it can probably be unplugged without removing or replacing it. I would try compressed air (or even an aerosol can of WD40 or something) to try dislodging whatever is plugging it up. I think the Husky tank vents are quite simple, usually just a rubber one-way flap.
 
Mine was some sort of a sintered doohinckus lodged deep in a recess in the tank housing. Not sure how I would have removed it. Reached in through the fill hole with a long punch and give it a poke, I guess.
 
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From the parts diagram I have I thought this was the tank vent. But I just went out and looked at the saw again and it doesn't seem to match up quite right. This parts diagram is a couple years older than my saw, though, so that might be a problem.

Now I'm totally bamboozled.
 

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Anyone know where to find up to date parts diagrams for Husky saws?
 
I have no idea on a Husky but is it possible it is vented through the cap???

I have never encountered a venting problem with a saw except some old Homelites on a real hot day. Venting will vary with different saws some are super fast other are on the slower side. The only way to verify venting on a saw is with a vaccum gauge connected to the fuel line with the tank empty. If the gauge shows vaccum and falls off quick then there is nothing wrong with the vent.

To me that hissing sound you hear when you crack the cap is a good sign to me that the tank is building pressure and holding that pressure. That pressure is what helps get fuel to the carb. The vent which is a one way valve that allows air to come into the tank as the fuel is consumed and the flow of fuel isn't vapor or vaccum locked in the tank.

Not saying you don't have a venting problem as they do occur but the problem might be else where.
 
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Thanks, that makes sense. I may have misdiagnosed my problem then. Any suggestions on what else might cause these symptoms?


EDIT: I will try pulling the fuel lines (there are 2 lines coming out of the tank) and blow them both out...
 
I've had just such a problem .It was on a Poulan 2800 which I ported .I solved the problem by installing an external vent such as the older Stihls used which solved the problem . It would be my assumption that the Husky vent might have a check valve arrangement in it .

Another thing .If the carb check valves are a little stiff this can pressurize the tank making the saw run erratic and cause the operator to exercise his or her mastery of the profane language .
 
Leon..
The IPL you have should be correct....
But if not there is a hose from same location up thru the plastic bottom of carb housing and in to the air filter elbow.
 
Most of the time a good cleaning from outside will do the trick for the vent.

It sounds as it is starving...
Have you tried opening L needle 10-20 minuts or so?

From what you describe I think you might have a stiff membrane, fuel line issue as a crack or bad pic up in tank.
Have a look at that too.
 
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Thanks Magnus those are good suggestions. A new fuel filter is probably in order anyways.

I do have that second hose coming out of the tank that you describe. It comes up into the carb housing along with the fuel line and then seemingly dead ends into a piece of solid plastic. I think that's the one to pull first and see if it's got stuff in it.
 
Run the saw with the gas cap off to check. I don't have mine here at home, but I think you can keep enough gas in to run for 5-10 minutes, or run it when laying on it's side.

Leon, do you know that on the 359 there was a parts recall on the funky plastic clip that holds the carb boot to the carb? The one from the factory was subject to warping and leaking air. They had a free replacement going, went to a metal band like in the old days. Your problem doesn't sound like an air leak, but when running, shoot some WD40 around the boot area and the engine will falter if you have a leak.
 
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I did not know that Jay. Thanks for the information. I was just looking at that clip today thinking it looked kind of dinky. Should any Husky dealer honor that?
 
Leon, its been quite awhile since the part recall was enacted, so it may be too late to get a freebie....not sure how that works....? The part should be cheap, it's just a thin metal band clamp. Baileys replaced mine through the mail, but that's also where I purchased the saw. Good question about any dealer or not, sorry I'm not clear on that.

I remember the problem with the defective part, is that it was subject to warping from heat, and then the air seal was lost. I'm wondering if when your saw gets hot, the clamp distorts? Mine went bad after about a year. I'd try your local dealer.
 
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Magnus, I knew what you meant, but thanks for the clarification. I don't the carb adjustment is the problem as the saw runs fine for the first 5 minutes or so, and thereafter runs fine as long as I open the fuel tank every few minutes, but I could be wrong.

Thanks for the tip on that Jay. I'll likely just wait until the clamp goes bad and then replace it.

After a bit more messing around with it yesterday evening I figured out that by removing the wrap handle and using a pair of long needle nosed pliers I could get the tank vent out. The tank vent is connected to a hose which runs up into the carb housing and terminates in a nipple up there. It did have a little bit of dirt in it, so I blew the whole thing out every which way, and hopefully that will solve the problem.
 
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I don't know yet. I blew out the vent and vent line, but haven't had a chance to run the saw for any good length of time yet. It may be a few days still, I'm involved with other stuff right now. Thanks for asking, though! :)
 
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OK I finally figured out the problem with this saw. I had replaced the tank vent, fuel filter, checked the fuel lines, etc. with no success. Yesterday I went into the Husky dealer in Taos (really nice guys there) and mentioned to one of the folks there that I had a 359. He told me that there was a tech bulletin put out faulting the carb on this saw. Apparently this carb doesn't do well with the new ethanol gasolines and one of the diaphragms starts decaying, or something along those lines.


Solution: replace with new model carb.
 
Oh Jay, you don't know the half of it. You cannot imagine all the problems generated when politicians mandate that oil companies start mixing 10% corn squeezings (ethanol) into our gasoline. Highly corrosive, unstable, absorbs moisture, reduces fuel economy, and ethanol producers are now making billions thanks to a stupid law.
 
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Not to mention we're taking agricultural fields out of food production and putting them into fuel production, which just does not seem wise to me.
 
I did hear awhile back that the Mexicans couldn't get the ingredients for their tortillas, which sounded rather illogical.

We're ten years behind the states in a lot of respects, so look for us to have the same political bad decisions and inadequacies, as time moves along.
 
I wondered why my tortillas were all stuck together at lunch, it's a conspiracy:/:
 
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