346 Tank Vent -- change em dang it!

[malk315]

I feel bad coming out of the woodwork to ask a question. I'm so behind on OPE lately

One of our 346's was having restart issues amongst other crappy running.
Today I changed fuel line, filter, impulse line, piston good, new muffler that has 2nd port single bull horn.

Set the needles 1 1/4 each and all over the place -- idling weird -- lean, then good, then lean.
WOT was good, then lean, then good. Clearly not right.

Put it aside and came back to it wondering about the tank vent. Pulled the tank vent and voila -- like a whole different saw holds tune perfect, idles perfect, sounds like the 10mm 044 I used to mess with w/ that muffler. Love it.

I can't run it w/ no tank vent -- just piss rev testing in the driveway it's great.

I have this style tank vent w/ no hose connected to it because this is an OE 346 w/ NE Cylinder thus no purge bulb or tank vent to carb box connection which usually connects to these:



It inserts with gray filter towards the tank and that nipple is just there w/ nothing connected.

The carb has just fuel inlet and no others (For purge bulb) it is a genuine Zama EL18B I got new when I had gone through this saw couple years ago.

NE 2011 and back 346 IPL shows a hose on this vent -- #5 in the picture below is the vent I included pic of above and is the problematic part:



Older IPL From 2001-2006 shows just these two "discs" for the tank vent.
I'm guessing this saw originally had this setup, but it's clear the tank on this saw has the vent w/ the nipple that fits right in really well so I probably need to stick with that. Below is the older IPL:




Questions for you guys are: Is it OK to run w/ the newer style vent that usually has a hose going to a purge bulb or carb or whatever w/ nothing connected? This has run for a while w/ just nothing connected at all to the vent nipple. If that is fine to run that way I'll go with that. Otherwise wondering if there is some kind of hose w/ a screen I should attach to keep debris out?

Tank vents are the most clueless for me. Hence reaching out.

Man what a difference pulling the clearly obstructed tank vent made. I want to run the saw tomorrow so bad because she's ripping, but I'll wait til I get a proper vent as I don't want crap going into the hole where this vent usually goes... Fines could get in there pretty easily w/ that hole exposed that normally has the vent shoved in.

Thanks for any info. Hope all of you guys are well!

 

[shadco]

See the echo tank vent tucked away here?




.

 

[malk315]

Yup. Line with white thingy on the end. I was thinking one of those. Have a part #?

It would be a little redundant since a screen is in the husky one and then that extra one but as long as it breathes and white thing keeps debris out.

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[malk315]

I actually looks like there is a hose that can be attached to the white vent nipple and run it up next to the fuel line into the carb box and there is a place to connect the hose on the black housing that the air filter mounts to etc. I'll probably go that route -- this saw ran fine for a while with now hose going from vent to carb box but I think it will do better with a hose going to the carb box because that setup will keep debris out of the nipple and allow it to breath clean air.

I found some more posts about the echo style filter and if I don't have an option to connect the hose in the carb box that echo style vent is perfect.

Thanks!

 

[kneedeepinsaws]

I feel bad coming out of the woodwork to ask a question. I'm so behind on OPE lately

One of our 346's was having restart issues amongst other crappy running.
Today I changed fuel line, filter, impulse line, piston good, new muffler that has 2nd port single bull horn.

Set the needles 1 1/4 each and all over the place -- idling weird -- lean, then good, then lean.
WOT was good, then lean, then good. Clearly not right.

Put it aside and came back to it wondering about the tank vent. Pulled the tank vent and voila -- like a whole different saw holds tune perfect, idles perfect, sounds like the 10mm 044 I used to mess with w/ that muffler. Love it.

I can't run it w/ no tank vent -- just piss rev testing in the driveway it's great.

I have this style tank vent w/ no hose connected to it because this is an OE 346 w/ NE Cylinder thus no purge bulb or tank vent to carb box connection which usually connects to these:

View attachment 253426

It inserts with gray filter towards the tank and that nipple is just there w/ nothing connected.

The carb has just fuel inlet and no others (For purge bulb) it is a genuine Zama EL18B I got new when I had gone through this saw couple years ago.

NE 2011 and back 346 IPL shows a hose on this vent -- #5 in the picture below is the vent I included pic of above and is the problematic part:

View attachment 253427

Older IPL From 2001-2006 shows just these two "discs" for the tank vent.
I'm guessing this saw originally had this setup, but it's clear the tank on this saw has the vent w/ the nipple that fits right in really well so I probably need to stick with that. Below is the older IPL:

View attachment 253428


Questions for you guys are: Is it OK to run w/ the newer style vent that usually has a hose going to a purge bulb or carb or whatever w/ nothing connected? This has run for a while w/ just nothing connected at all to the vent nipple. If that is fine to run that way I'll go with that. Otherwise wondering if there is some kind of hose w/ a screen I should attach to keep debris out?

Tank vents are the most clueless for me. Hence reaching out.

Man what a difference pulling the clearly obstructed tank vent made. I want to run the saw tomorrow so bad because she's ripping, but I'll wait til I get a proper vent as I don't want crap going into the hole where this vent usually goes... Fines could get in there pretty easily w/ that hole exposed that normally has the vent shoved in.

Thanks for any info. Hope all of you guys are well!

can you clean those style vents? I only ask because they are 2 weeks wait time where i am... it looks like a piece of sintered brake pad. Did yours look dirty or did it look new and was clogged?

 

[malk315]

I know @Mattyo mentioned in a video cleaning with compressed air. My concern is older gas getting gummed up etc. I have a few on order... Expensive buggers but I'm thinking if I change em on our 346's and 350 it will be good preventive. Changing fuel and impulse lines on these too and the 350 has purge bulb changing bulb and using some tigon line to replace those lines on that saw.

I found two tank styles.... One with orange nipple for purge bulb return next to vent and one with just the vent. I plan to run the vent nipple with line up onto carb box at the front right on the floor is a nipple to connect. Some have a nipple on the black tube the filter sits on but not my case. Both 346 are OE no purge bulb and it is nice to run a tube from vent to nipple on carb box to help keep debris out of the vent. Another option is to put an echo vent (breather) on there... I ordered a couple in case that is an option... Redundant vent at that point... Also helps with gas weeping so common problem.


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[EvilRoySlade]

Last I recall was knock guts out of OEM vent then reinstall with hose to echo vent. I’ve ran just oem no hose, oem with rubber check flap removed, and oem discs all pretty well.

 

[Mattyo]

I'm liking the echo style vents lately.. but on these often I just use the pucks and then take my soldering iron and lightly touch the plastic so it melts enough to hold the puck in

 

[malk315]

BTW -- the vent I removed didn't look dirty, but I could not pass air through it -- if I sucked air through really hard it made this tiny whistle noise letting tiny bit of air through... kicked to the curb!

Man did it raise havoc for the saw -- rich, then lean, tuning efforts were like what the hell? wouldn't idle.

Took the vent out and just ran in clean environment on my driveway -- set the needles back to 1 1/4 turns out on each and the saw runs perfect. I'll put the new vent in and fine tune it ... but the needles are actually quite decent where they are at... it's not gonna take much. I did a test of letting it sit and idle for like 5 minutes -- picked it up and piss rev no hesitation, idle is clean, WOT is a nice 4 cycle doing about 13K. I'll get up towards 13.5 for some margin and set the low half way between drop off rich and racing idle lean... When the vent was bad, the low needle I could not richen to not have it come up in RPMS.... starving for gas that needle wasn't going to do anything and would race at idle and quit... restart sucked... sometimes had to pull choke... basket case.

Carb was brand new EL18B genuine Zama when I rebuilt the saw everything except case split. I didn't do the vent and had a home-made impulse line. Now it has new fuel filter, line, vent, vent line to carb box (I'll cut tigon for this and check the nipple in the carb box flows free -- if not, I'll put and echo vent on the end), OEM impulse hose, and that new single bull horn / dual port muffler. Already has base gasket delete. Excited to get her back on the truck for tree work -- hopefully Saturday.

The echo vents are only about $5.00 compared to $13-15 for the husky one. You could take an old husky vent and remove the material so you just have the vent housing to insert into the tank and then connect a small section of hose to it and route it up one of the holds to the carb box and stick the echo vent on there. $5.00 repair instead of $15.00.

E-Replacement parts has the echo vents in stock -- $6.00

https://www.ereplacementparts.com/assy-vent-p-974544.html

Jacks small engines for $5.41

https://www.jackssmallengines.com/jacks-parts-lookup/part/echo/13130056431

To save you could probably have echo dealer get a few and avoid shipping charges. Great alternative if your old vent you can remove the venting material and re-install w/ a bit of hose.

Sticking with OEM husky fuel hose / filter / and impulse. For the other hoses that do the purge bulb on the 350 I'm using tygon 0.211 OD and 0.117 ID which was noted as that size used by a husky dealer. You can buy this by the foot from Jack's and I grabbed like 15' for about $10.00 to save and have line available in a pinch being such a common issue.

Cheers.

 

[huskyboy]

I feel bad coming out of the woodwork to ask a question. I'm so behind on OPE lately

One of our 346's was having restart issues amongst other crappy running.
Today I changed fuel line, filter, impulse line, piston good, new muffler that has 2nd port single bull horn.

Set the needles 1 1/4 each and all over the place -- idling weird -- lean, then good, then lean.
WOT was good, then lean, then good. Clearly not right.

Put it aside and came back to it wondering about the tank vent. Pulled the tank vent and voila -- like a whole different saw holds tune perfect, idles perfect, sounds like the 10mm 044 I used to mess with w/ that muffler. Love it.

I can't run it w/ no tank vent -- just piss rev testing in the driveway it's great.

I have this style tank vent w/ no hose connected to it because this is an OE 346 w/ NE Cylinder thus no purge bulb or tank vent to carb box connection which usually connects to these:

View attachment 253426

It inserts with gray filter towards the tank and that nipple is just there w/ nothing connected.

The carb has just fuel inlet and no others (For purge bulb) it is a genuine Zama EL18B I got new when I had gone through this saw couple years ago.

NE 2011 and back 346 IPL shows a hose on this vent -- #5 in the picture below is the vent I included pic of above and is the problematic part:

View attachment 253427

Older IPL From 2001-2006 shows just these two "discs" for the tank vent.
I'm guessing this saw originally had this setup, but it's clear the tank on this saw has the vent w/ the nipple that fits right in really well so I probably need to stick with that. Below is the older IPL:

View attachment 253428


Questions for you guys are: Is it OK to run w/ the newer style vent that usually has a hose going to a purge bulb or carb or whatever w/ nothing connected? This has run for a while w/ just nothing connected at all to the vent nipple. If that is fine to run that way I'll go with that. Otherwise wondering if there is some kind of hose w/ a screen I should attach to keep debris out?

Tank vents are the most clueless for me. Hence reaching out.

Man what a difference pulling the clearly obstructed tank vent made. I want to run the saw tomorrow so bad because she's ripping, but I'll wait til I get a proper vent as I don't want crap going into the hole where this vent usually goes... Fines could get in there pretty easily w/ that hole exposed that normally has the vent shoved in.

Thanks for any info. Hope all of you guys are well!

Yes it is ok to run those vents with nothing connected. New 562’s come that way from the factory. They used to have the tube going to the intake but they got rid of that because in hot weather the vent would weep into the intake flooding the saw. 372’s and 572’s they use the same vent too and are connected to a nipple in the intake box, not the intake. Which is a better design. Idk what they were thinking with originally routing it to intake, really a dumb idea.

 

[malk315]

Yes it is ok to run those vents with nothing connected. New 562’s come that way from the factory. They used to have the tube going to the intake but they got rid of that because in hot weather the vent would weep into the intake flooding the saw. 372’s and 572’s they use the same vent too and are connected to a nipple in the intake box, not the intake. Which is a better design. Idk what they were thinking with originally routing it to intake, really a dumb idea.

Hey Mason! Thanks for tips. I believe on the 2 x 346's w/ no primer bulb (OE chassis w/ NE 50CC top ends) they both have that nipple on the floor of the carb box quite close to the impulse hose up at the front. I'll probably run a tube from the vent up to that nipple provided that nipple flows freely. The thought is less crap to get built up -- one of the 346's has it setup like this. The second one just had the vent on it's own w/ no hose. I agree the vent going to intake seems odd -- the vent just needs to be open to the atmosphere -- going into the black tube the air filter sits on will have different pressure going on when the saw is drawing air at WOT vs idle etc. and yes -- if the vent weeps, fuel is going to head into the carb throat causing a nice flood.

Do you by any chance know where the nipple on the floor of the carb box up by the impulse hose actually goes? I'm guessing it just goes through the floor to atmosphere by the back of the cylinder head... to simply breathe.

 

[malk315]

Pics from when piss rev testing after vent removed and new fuel filter, line, impulse, and the single bull horn muffler. Exited to get her back in the wood.

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[kneedeepinsaws]

Yes it is ok to run those vents with nothing connected. New 562’s come that way from the factory. They used to have the tube going to the intake but they got rid of that because in hot weather the vent would weep into the intake flooding the saw. 372’s and 572’s they use the same vent too and are connected to a nipple in the intake box, not the intake. Which is a better design. Idk what they were thinking with originally routing it to intake, really a dumb idea.

I think that is an emissions thing. Running vents back to the intake is extremely common for other small engine equipment. The idea is the vapours are burned by the engine instead of going to the atmosphere. Cars use an evap canistor with charcoal nullifying the toxic odours...
these puck vents i dont like and much prefer the duckbill one way valves. Has anyone put a duckbill on their 562/372?

 

[malk315]

I think that is an emissions thing. Running vents back to the intake is extremely common for other small engine equipment. The idea is the vapours are burned by the engine instead of going to the atmosphere. Cars use an evap canistor with charcoal nullifying the toxic odours...
these puck vents i dont like and much prefer the duckbill one way valves. Has anyone put a duckbill on their 562/372?

Thanks man -- that makes a lot of sense. If I get annoyed trying to run a tube for the vent I'll ditch that and just run it without!
We do get a lot of fines buildup on top of gas tank under the carb box... trying to keep the vent clear is all.

With a one way valve that allows air to come in as the carb draws off the tank but not allow to escape the other way -- if you leave the saw out in the sun, tank pressure will build and that one way valve won't let the air out. This is where I'm a fan of air flow in both directions. Maybe the echo breather is a good compromise?

 

[huskyboy]

Hey Mason! Thanks for tips. I believe on the 2 x 346's w/ no primer bulb (OE chassis w/ NE 50CC top ends) they both have that nipple on the floor of the carb box quite close to the impulse hose up at the front. I'll probably run a tube from the vent up to that nipple provided that nipple flows freely. The thought is less crap to get built up -- one of the 346's has it setup like this. The second one just had the vent on it's own w/ no hose. I agree the vent going to intake seems odd -- the vent just needs to be open to the atmosphere -- going into the black tube the air filter sits on will have different pressure going on when the saw is drawing air at WOT vs idle etc. and yes -- if the vent weeps, fuel is going to head into the carb throat causing a nice flood.

Do you by any chance know where the nipple on the floor of the carb box up by the impulse hose actually goes? I'm guessing it just goes through the floor to atmosphere by the back of the cylinder head... to simply breathe.

Idk where it leads on a 346 but on a 372 and a 572 it just loops around to the bottom of the carb box from what I can tell

 

[Mattyo]

It loops into the carb box and down to the nipple on the carb base....venting under the carb base....which is weird. Might as well not loop it around lol. I leave my duck bills in the carb box. I'll actually drill out the tank vents in the gas tanks to accept rubber line instead of the black tank vent tube on a 372. The rubber line just goes into the tank a few inches and then up into the carb box to a duck bill. Seems to make more sense this way.

 

[kneedeepinsaws]

It loops into the carb box and down to the nipple on the carb base....venting under the carb base....which is weird. Might as well not loop it around lol. I leave my duck bills in the carb box. I'll actually drill out the tank vents in the gas tanks to accept rubber line instead of the black tank vent tube on a 372. The rubber line just goes into the tank a few inches and then up into the carb box to a duck bill. Seems to make more sense this way.

to me, the approach that husky is trying to make having the vent come up and then loop down to a nipple is for keeping it clean. Fines are far less likely to go up and then down the vent tube rather than just down due to gravity.

mattyo do you have a picture of your duckbill setup?

 

[Mattyo]

No....its in my videos somewhere though. Next time I'm into a carb box ill try to get pix