357xp tank vent or other possible problem

[deezle_dog]

My husqvarna has been giving me some problems lately. It will start good now after a carb adjustment, but after warming up, I can cut through maybe 3 or 4 8" logs and it will start to die if I let it go back to an idle. I can feather the throttle while opening the gas cap for a second, and it will smooth back out. I also tried opening the gas cap after each cut, and I never had a problem with it not idling until I stopped opening the cap.

My question is, is there something besides the tank vent that could have the same symptoms as I am experiencing? Or could there be a problem with the carb or impulse that could make it difficult to overcome the tank vent? I can blow through the tank vent, but it isn't easy. I don't know much air it needs or how easy it should be to blow through the vent tube into the tank.

Thanks for your help
Deezle

 

[HiOctane]

Try opening the fuel cap and listen to hissing air.If you hear some air escaping,then your vent is blocked.Usually replacing the white"dime" will bring everything ok.Are you cutting in snow condition ?If you keep having problem,i would open the carb.Look too for the condition of the impulse line.And if you still have same symptom,then a pressure is next.

 

[Grande Dog]

Sounds most like a tank vent. Shade-tree check is to fill the saw with fuel. Lay it on it's side with the fuel cap pointing up. Disconnect the fuel line. You should get a steady stream. If it slows down to a drip or stops, crack the fuel cap. If it starts flowing again, you'll know the vent is involved.

 

[blsnelling]

Try opening the fuel cap and listen to hissing air.If you hear some air escaping,then your vent is blocked.

Tanks vents are usually a one-way valve the prevents vacuum, not pressure. Matter of fact, the valve would cause pressure buildup with a temp change.

 

[HiOctane]

Tanks vents are usually a one-way valve the prevents vacuum, not pressure. Matter of fact, the valve would cause pressure buildup with a temp change.

You are right.

 

[wkpoor]

I recently posted on this just days ago with almost the same issue on a 395XP. I don't know what the vent looks like on your saw but if it is a similar setup I can help. The 395 uses a check valve in a long white nylon tube pushed through from the R/H side of the tank under the carb housing. The valve is not visible as its under 2 sintered bronze filters. It can be removed however. I removed mine and left the filters in and the saw runs perfect now.

 

[blsnelling]

I'm glad to hear that Bill.

 

[deezle_dog]

Grande Dog, I will try the shade tree method tomorrow. With the amount of effort it took for me to blow through the tank, I don't think that gravity alone will overcome the vent. What do you guys think about drilling the vent out. I have been told by some that this will help. Also if I drill out the tank vent, is there an in-line check valve I could place in the hose that connects to the vent?

Thanks for the help
Deezle

 

[wkpoor]

You cannot drill the vent. The first thing I tried was to drill the bronze with a #70 drill. Its a no can do. The easiest thing is to remove the tube and punch out the guts from the small end. Reinstall only the filters and leave the filter in the hose end. Leave out the rubber check valve and seat. I have noticed no leakage from mine and the tank is now fully vented at all times.

 

[dustytools]

I recently posted on this just days ago with almost the same issue on a 395XP. I don't know what the vent looks like on your saw but if it is a similar setup I can help. The 395 uses a check valve in a long white nylon tube pushed through from the R/H side of the tank under the carb housing. The valve is not visible as its under 2 sintered bronze filters. It can be removed however. I removed mine and left the filters in and the saw runs perfect now.

Im glad you got things worked out Bill! :greenchainsaw:

 

[deezle_dog]

You cannot drill the vent. The first thing I tried was to drill the bronze with a #70 drill. Its a no can do.

The tank vent in my 357xp is made from white plastic. It would be easily drilled I think since it is just plastic. It is also molded into the tank.

Some have told me that the entire handle/tank assembly has to be replaced because the tank vent(check valve) is not replaceable. Is this true?

So you haven't had any trouble with the check valve removed? That sounds good.

Thanks All
Deezle

 

[wkpoor]

The vent is not molded in if its like the 395. It simply pushes in with a tight fit. However the trick is removal. You will need a pair of long bent nose needle pliers to gently grab from inside the tank and push outwards. There are 2 green pieces that attach to it. One is a 90 that adapts to the hose. They all snap apart. You cannot drill the plastic as that will not help at all. After the tube is removed use a small dia. rigid wire to tap out the guts of the tube from the small end. You will then see the rubber check valve. only reinstall the 2 small bronze filters by pushing them all the way into the big end of the tube till they seat tight. Then reinstall all other parts like they were. Walla vent problems are over. Thankyou EPA NOT!

 

[Poley4]

I have a problem with the tank vent on my 306A Poulan. It is a duckbill piece in the fuel cap. When I fill up the saw and let it sit, the tank builds up pressure and I guess pushes the needle valve off of the seat in the carb and floods the engine to the point that gas will run out onto the floor. I changed the fuel cap with one that doesn't have the duckbill valve and that cured the flooding problem, but now when I fill the saw and run the saw, it squirts fuel all over my hand. Not cool!

 

[deezle_dog]

Well Wkpoor, you were right. It wasn't molded into the tank. I just pulled off the hose, grabbed the nipple with some needle nose pliers, and pulled it out. I removed the check valve, and the bronze filters. I put it all back together and maneuvered the saw around a bit to see if it was going to leak, and everything looked fine. I cut with it for a few minutes(probably 20 cuts in 12" maple) and it ran perfect. Before I would have gotten 2 or maybe 3 cuts if I was lucky.

Many Thanks,
Deezle

 

[blsnelling]

So what's up with these Husky tank vents? Seriously.

 

[PES+]

If you leave the saw on it's side chain side down with the vent gutted they will weep fuel.

If you can live with it go for it.

The vents do go bad and are not expensive to replace.

On the 306A you have a bad needle and seat seal, a soft lever spring and possibly a leaky governor valve or all of the above.

Pressure test the carburetor and see if it will hold pressure.

 

[deezle_dog]

I didn't see anything wrong with the internals of the check valve. I am just wondering if something could be wrong with the carb, making it struggle to pull in fuel at an idle?

I don't know, but now that the vent is "open", it starts and runs much better.

Now I can't help but think about a muffler mod :greenchainsaw:

Deezle

 

[PES+]

I didn't see anything wrong with the internals of the check valve. I am just wondering if something could be wrong with the carb, making it struggle to pull in fuel at an idle?

I don't know, but now that the vent is "open", it starts and runs much better.

Now I can't help but think about a muffler mod :greenchainsaw:

Deezle

Since you have the newer style vent with the hose that routes into the air box I would check the flow through the nipple that the vent line goes to in the air box. The hole in the nipple is very small and can clog pretty easily.

I have seen some brand new that the hole is almost closed tight with plastic flash.

 

[blsnelling]

The vents do go bad and are not expensive to replace.

wkpoor's 395XP is brand new and had this problem

 

[PES+]

They can be bad new as well. It should have been a warranty item.