cjcocn
Tree Freak
Okay, now I am really confused?
Is my pic a duckbill valve, or not a duckbill valve?
Poulan 3400 3700 4000 etc fuel lines
- Thread starter Modifiedmark
- Start date
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Okay, now I am really confused?
Is my pic a duckbill valve, or not a duckbill valve?
Exactly and the long end goes into the fuel line in the tank, while the duckbill slips on the short end.
Chris, go back to post one and see the red Homelite duckbill valve in the picture. I'm not sure the shorter Homelite valve will fit on the barbed fitting as the Poulan original is longer. Thats why I showed it on a piece of 1/8" plastic line since the original barbs are lost most of the time and are NLA anyway.
cjcocn
Tree Freak
Okay. So I don't have one. Thanks.
I will order some up from E&E unless I can find some locally (I highly doubt it!).
Another Bucker
ArboristSite Operative
Mark
Great write-up and pics. Thanks!
I stripped my 3400 this evening and now have to order rings and a carb kit, and buy some fuel lines. I understand that the cylinder gasket is NLA so I will cut my own.
I have a question on the duckbill valve. I am not sure if mine is complete since it had a glob of black junk on it. The black junk was soft and wiped off easily with a rag.
Is the remaining piece a complete duckbill valve?
Here is a pic:
If so, I should be able to order the items that I mentioned above then it is off to the races.
Thanks, Mark!
530026119 is the poulan duckbill to fit this... ditto on the great thread, sorry i missed it when it was first posted.
vw_motorsports
ArboristSite Guru
pics always better than words
What are you referring to?
Fudpucker
New Member
More info about duckbill valve in 3400
I have 2 3400's purchased new in 1986. One i have been using and one still unused, in storage. On reading this thread, I looked inside the fuel tank on the used saw and noticed there was no ducbill on the exposed bib; nor were there any remnants in the tank. Being curious, I retrieved the unused saw and looked in the tank. Same situation-no duckbill.
I then pulled the recoil plate off the first saw and pulled the vent line out of where it was tucked. I discovered that the duckbill had been pinched and stuck in the end of the line, valve end first, with the bib end snipped off. I then decided to check the unused saw. It was the same. Obviusly, at least one person at the assmbly plant was doing it this way. maybe they discovered they had a bad supply of valves that did not tolerate gasoline immersion and this was a workaround procedure. In any event, if the duckbill valve is missing from the inside of your tank, don't assume there ever was one in there. You may find it stuck in the end of the vent line.
I have 2 3400's purchased new in 1986. One i have been using and one still unused, in storage. On reading this thread, I looked inside the fuel tank on the used saw and noticed there was no ducbill on the exposed bib; nor were there any remnants in the tank. Being curious, I retrieved the unused saw and looked in the tank. Same situation-no duckbill.
I then pulled the recoil plate off the first saw and pulled the vent line out of where it was tucked. I discovered that the duckbill had been pinched and stuck in the end of the line, valve end first, with the bib end snipped off. I then decided to check the unused saw. It was the same. Obviusly, at least one person at the assmbly plant was doing it this way. maybe they discovered they had a bad supply of valves that did not tolerate gasoline immersion and this was a workaround procedure. In any event, if the duckbill valve is missing from the inside of your tank, don't assume there ever was one in there. You may find it stuck in the end of the vent line.
lawnmowertech37
Addicted to ArboristSite
I've had an issue I can't pin down with a little Poulan I put a vent line on. When I tip the saw over to gas it up, even with the vent hose up in the vertical position gas just pours out the vent. I've got a screw in it right now but it still has a huge leak, just like it is pressurized. I vented my Poulan Weedeater this way but the saw isn't cooperating.
rms61moparman
Addicted to ArboristSite
Is your vent line at the top of the tank?
If they slip down into the tank they get fuel and not air.
Sounds like you need a bigger screw.
Mike
If they slip down into the tank they get fuel and not air.
Sounds like you need a bigger screw.
Mike
You're probably right..the vent is sticking down in tank too far. I may have to go with duckbill valve rather than the screw. When Stihl used the screw in their vents they also used a foam piece to catch the fuel and routed the line toward the clutch side. I hate the idea of vented caps unless the caps are on the top of the engine.
stubnail67
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wish they did not loose these pics that mark had posted
stubnail67
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SO I JUST GOT A REALLY REALLY NICE 3.7....for 20 bucks piston is nice compression is good.....i know i suck .....any ways they guy tried to run the fuel lines they were wrong... I redid the lines cleaned the carb inspected it....he had the right kit just had it backwards put it back together set it at 1 turn out each high and low low had to go out a lil for throttle response on the low....not worried about that but the high had to come in to about 3/4 of a turn to sound decent out of wood......turn it in it smooths out at 3/4 he also lost the spring on the idle screw i had one he also stepped on the air filter so he said....it has the power sharp and the original bar and chain im stoked...... are the needle;s one these interchangeable????could he have ham fisted one in the wrong hole?????i always thought the needles were a lil different should i swap them out???? this saw is to nice to burn up..... picks once it cools down.....20 bucks OWWWWWWWWWWWWWWWWWW!!!!! finally .... it has the walbro carb....
rms61moparman
Addicted to ArboristSite
No the needles aren't interchangeable.
They are two different lengths and thread sizes.
Could be wear in the carb I would set the high side to 1 turn and cut with it for a half day or so before I ran it any leaner.
Mike
Bad advise Mike, yes they are the same needles on the Walbro HDB 8 carbs that 3400-4000 series uses. I just happen to be rebuilding one now.
stubnail67
Addicted to ArboristSite
i thought so..... the holes look the same... i have another carb i know is good just dirty.....from the one i had with a bad piston think i will rebuild it with a new kit order a filter and replace the bar and chain it runs starts right up the needles are way off...I thought they felt weird they were 4 turns out or more .... its to nice a piston to screw it up i can wait till i get the proper parts.....on the carb is K10-HDB. the right kit?
stubnail67
Addicted to ArboristSite
now im confused LOL my needle look the same .... didn't use my new glasses its holding an idle and reving fine just pig rich out of wood ..... oiler works best 20 buck i ever spent.....
stubnail67
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stubnail67
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ok so i put it all back together minus the air filter... and retuned it and its pretty close.... maybe from being run maybe yoy should have the engine and air filter cover on it????? im just happy happy to have got a great deal... i was getting rid of my one with a bad piston but im glad i have it for parts now....will wait till i get a air filter then sharpen the chain and put it in wood and retune her...im so used to tuning the micros with the hood off did not think it made any difference?????could just need to be run a lil....Life is good!
