Nik's Poulan Thread

[hotshot]

now I'm noticing that the longer the saw is running and the warmer it gets that it starts to bog down. First it doesn't want to idle without throttle, then eventually the throttle starts bogging down too and it dies. Have to let it sit for awhile before you can restart it. Interestingly the Hi/Lo screws appear to be having little to no effect. Think I still have a problem somewhere in the carb?

Sounds more like a plugged up duckbill valve on the end of the fuel tank vent hose inside the tank.

But, it could also have air leaking around the intake gasket or the crank seals when she warms up.

Did you do a vacuum & pressure test before running it?, as that saw’s well over 30 years old!

 

[banshee1]

View attachment 856847
This ignition for the 3400.

Mine came in a couple days ago. Hope to get it on the Poulan tomorrow and do a couple test cuts with new bar and chain. I'll check spark and let you know it does. Short term anyways.

 

[Jethro 2t sniffer]

Cut the gum on the left today a touch bigger than a 32 Windsor bar.

excuse the yellow saw but I don't have a big poulan yet.

The green 4000 was the limbing machine today again. Absolutely love it tank after tank after tank. Last outing I took my usual 4 or 5 saws but that 4000 never missed a beat so other than the 850 thats all I took today its dead reliable so far.
Messy trees not as bad as the macro's but still messy.

Grandfather on the wee top handle

Now hears the cool part. My workmate has a husky 576 last week was kinda sick so its had a new carb (warranty) and this week the 4000 still out cuts it easily in 18 inch wood. Perhaps I'm better on the file I spose but yeah he didn't say a word lol and to be fair his has a 24 and semi chisel too. That 4000 rips hard though and sounds great the land owner loves it aaaaaand.... 1 pull today from cold lol 2nd time its done that now. 40 year old saw (its a 79 3400 chassis) runs like a new 1. Its probably still on original crank seals even. Not that I condone that but it certainly doesn't run like its got a leak

 

[redunshee]

Good score! Let’s us know how much compression psi it has, I wish I could find the info on how much the 3400-3800-4000 should have?

The 3400 typically has about 120-125 compression. 135 is real good. 3700's and 4000's typically higher and more in line with other manufacturers e.g. 150 or more. I've seen 175 on a 4000 sans cylinder gasket.

 

[redunshee]

Anybody see the NOS 3450 on Ebay? If it were a type 3 I might be tempted.

 

[hotshot]

The 3400 typically has about 120-125 compression. 135 is real good. 3700's and 4000's typically higher and more in line with other manufacturers e.g. 150 or more. I've seen 175 on a 4000 sans cylinder gasket.

Good morning Bob.

Did you figure out that Poulan 3400 ‘skipping‘ starter issue? I posted the same question back on Oct 3, but never heard.

 

[RedneckChainsawRepair]

Anybody see the NOS 3450 on Ebay? If it were a type 3 I might be tempted.

Is it the guy from NC or SC? He has been selling them for years now if so. He bought pallets of them.

If so he even has them listed here over the years in FS section too.

UPDATE: Not same guy being shows WI. Plus it is even more then the other seller of the NOS ones. Other guy was 3's last time I recall.

 

[redunshee]

Good morning Bob.

Did you figure out that Poulan 3400 ‘skipping‘ starter issue? I posted the same question back on Oct 3, but never heard.

Not exactly and i haven't looked at it in a while. Maybe this weekend. Nice and cool here.

Sent from my SM-G935V using Tapatalk

 

[McCullochKid]

Sounds more like a plugged up duckbill valve on the end of the fuel tank vent hose inside the tank.

But, it could also have air leaking around the intake gasket or the crank seals when she warms up.

Did you do a vacuum & pressure test before running it?, as that saw’s well over 30 years old!

I don't think it has anything with the fuel tank being plugged up, as I got new fuel line, fuel filter, and breather line with a new duckbill put in. I'm able to blow air through that into the tank easily enough.

The more research I do on air leaks, the more it looks like a likely culprit of what's going on with this saw. Unfortunately, I don't have any of the equipment to do things like pressure/vacuum tests yet.
Another thing I noticed that possibly supports a leak happening is that once you get it started and idling/revving cold, which it does just fine, if you listen carefully it slowly starts idling faster and faster as it warms up, until it reaches the point where it either bogs down and dies during idle or when you give it any throttle. Trying to restart it after that when its warmed up just floods it

At least I don't have my idle screw vibrating out anymore. lol

 

[redunshee]

Not exactly and i haven't looked at it in a while. Maybe this weekend. Nice and cool here.

Sent from my SM-G935V using Tapatalk

Looked at saw. Was bi#$& to start but once it started it ran fine. Comp around 118. Not great but not bad. However after sitting for an hour it wouldn’t restart. Dry plug. Removed fuel line from carb and fuel squirted out of line strongly. I suspected a blocked vent line but after doing a tank pressure and vacuum test, everything passed. Held pressure but not vacuum. Any suggestions?

 

[hotshot]

Looked at saw. Was bi#$& to start but once it started it ran fine. Comp around 118. Not great but not bad. However after sitting for an hour it wouldn’t restart. Dry plug. Removed fuel line from carb and fuel squirted out of line strongly. I suspected a blocked vent line but after doing a tank pressure and vacuum test, everything passed. Held pressure but not vacuum. Any suggestions?

I was asking about the 3400 starter pawls “skipping” , but I guess that part is working fine now.

Other “dry plug” issue sounds like the carb needs inspected inside. Pull the metering plate & check for the correct plate gasket, check the little nozzle screen for debris, then vac/blow test that main nozzle check valve with a piece of tubing.

Reset the metering lever height, & last the choke plate needs checked to be fully closed with the knob pulled out.

All the things that I can think of...I assume it’s an HDB Walbro with good diaphragms. Right bottom is the 3400 circuit gasket.

 

[redunshee]

I was asking about the 3400 starter pawls “skipping” , but I guess that part is working fine now.

Other “dry plug” issue sounds like the carb needs inspected inside. Pull the metering plate & check for the correct plate gasket, check the little nozzle screen for debris, then vac/blow test that main nozzle check valve with a piece of tubing.

Reset the metering lever height, & last the choke plate needs checked to be fully closed with the knob pulled out.

All the things that I can think of...I assume it’s an HDB Walbro with good diaphragms. Right bottom is the 3400 circuit gasket.

View attachment 862029View attachment 862054

No,the pawls seem to still skip a bit. Still need addressing. Guess I’m unsure of what part ur referring to when you say, “ blow into the hose connected to the main check valve nozzle.”

 

[hotshot]

“then vac/blow test that main nozzle check valve with a piece of tubing“, means to make sure the little black nitrile disc check valve located under the nozzle screen is working correctly.

Should be able to press a short ~6” piece of fuel line over/against the brass nozzle, then blow air through it. Should NOT be able to pull air back through it. I’ll tear one down & take a picture this evening.

 

[redunshee]

“then vac/blow test that main nozzle check valve with a piece of tubing“, means to make sure the little black nitrile disc check valve located under the nozzle screen is working correctly.

Should be able to press a short ~6” piece of fuel line over/against the brass nozzle, then blow air through it. Should NOT be able to pull air back through it. I’ll tear one down & take a picture this evening.

I assume that contains that little screen with small circular ring that retains the screen. I noticed that the screen was missing. Black nitrile disc looks good but I’ll inspect further.

 

[McCullochKid]

I think I discovered a big clue just now. Just to try and eliminate possible causes of my woes with the 3800 I checked the fuel/breather line yet again, pulled the carb out and took it apart again to make sure I got everything reassembled the way it should be, and then I took the spark screen/baffle out of the muffler.

With this being done, I went and gave it another attempt from a cold start, except this time I was armed with a tip I discovered from an old post on here to try and help diagnose an air leak without any tools by simply experimenting with turning the saw on its side in different directions while running and seeing how it reacts.
A few observations after the saw warmed up a bit through idling...
1: Turning the saw on its right side(clutch side down) makes it want to bog down and puff out smoke from the exhaust.
2:Turning the saw on its left side stabilizes the idle when the saw would otherwise bog down and die, and from that point the rpm slowly increases the longer its held in that position.
3: Pointing the saw down doesn't seem to do anything, while pointing it up seems to slightly help it run, but not nearly as much as holding it on its left side.
4: The saw seems to run better without the spark screen/baffle, even with its problems. Is this why people muffler mod? Also, it just plain sounds better now.

Would this imply that the crank seal on the flywheel side is bad?

 

[redunshee]

I think I discovered a big clue just now. Just to try and eliminate possible causes of my woes with the 3800 I checked the fuel/breather line yet again, pulled the carb out and took it apart again to make sure I got everything reassembled the way it should be, and then I took the spark screen/baffle out of the muffler.

With this being done, I went and gave it another attempt from a cold start, except this time I was armed with a tip I discovered from an old post on here to try and help diagnose an air leak without any tools by simply experimenting with turning the saw on its side in different directions while running and seeing how it reacts.
A few observations after the saw warmed up a bit through idling...
1: Turning the saw on its right side(clutch side down) makes it want to bog down and puff out smoke from the exhaust.
2:Turning the saw on its left side stabilizes the idle when the saw would otherwise bog down and die, and from that point the rpm slowly increases the longer its held in that position.
3: Pointing the saw down doesn't seem to do anything, while pointing it up seems to slightly help it run, but not nearly as much as holding it on its left side.
4: The saw seems to run better without the spark screen/baffle, even with its problems. Is this why people muffler mod? Also, it just plain sounds better now.

Would this imply that the crank seal on the flywheel side is bad?

Yup. Thats a good test sans a pressure/vac test. Best bet is to replace both seals seeing how ur replacing one. I always remove the spark screen and also enlarge the baffle holes. However I’m
not cutting on Public land.

 

[hotshot]

I assume that contains that little screen with small circular ring that retains the screen. I noticed that the screen was missing. Black nitrile disc looks good but I’ll inspect further.

The discs may “look“ OK, but can fail air testing. Here’s a pic of the tube at the nozzle, I use a piece of silicone tubing as it's more flexible.



This one “looked“ good, but failed vacuum as it was hardened up, so I just replaced it...comes as an assembly #86-523 so you don’t have to try to put the screen & that tiny midget clip back in.

Drilled & tapped thread #6-48 (same as rifle scope mounts), put in a short screw, & then levered it out. You could also just pry it out with a pic.

 

[redunshee]

I think I discovered a big clue just now. Just to try and eliminate possible causes of my woes with the 3800 I checked the fuel/breather line yet again, pulled the carb out and took it apart again to make sure I got everything reassembled the way it should be, and then I took the spark screen/baffle out of the muffler.

With this being done, I went and gave it another attempt from a cold start, except this time I was armed with a tip I discovered from an old post on here to try and help diagnose an air leak without any tools by simply experimenting with turning the saw on its side in different directions while running and seeing how it reacts.
A few observations after the saw warmed up a bit through idling...
1: Turning the saw on its right side(clutch side down) makes it want to bog down and puff out smoke from the exhaust.
2:Turning the saw on its left side stabilizes the idle when the saw would otherwise bog down and die, and from that point the rpm slowly increases the longer its held in that position.
3: Pointing the saw down doesn't seem to do anything, while pointing it up seems to slightly help it run, but not nearly as much as holding it on its left side.
4: The saw seems to run better without the spark screen/baffle, even with its problems. Is this why people muffler mod? Also, it just plain sounds better now.

Would this imply that the crank seal on the flywheel side is bad?

Yup. Thats a good test sans a pressure/vac test. Best bet is to replace both seals seeing how ur replacing one. I always remove the spark screen and also enlarge the baffle holes. However I’m
not cutting on Public land.

The discs may “look“ OK, but can fail air testing. Here’s a pic of the tube at the nozzle, I use a piece of silicone tubing as it's more flexible.

View attachment 862085

This one “looked“ good, but failed vacuum as it was hardened up, so I just replaced it...comes as an assembly #86-523 so you don’t have to try to put the screen & that tiny midget clip back in.

Drilled & tapped thread #6-48 (same as rifle scope mounts), put in a short screw, & then levered it out. You could also just pry it out with a pic.

View attachment 862086View attachment 862087View attachment 862088

The discs may “look“ OK, but can fail air testing. Here’s a pic of the tube at the nozzle, I use a piece of silicone tubing as it's more flexible.

View attachment 862085

This one “looked“ good, but failed vacuum as it was hardened up, so I just replaced it...comes as an assembly #86-523 so you don’t have to try to put the screen & that tiny midget clip back in.

Drilled & tapped thread #6-48 (same as rifle scope mounts), put in a short screw, & then levered it out. You could also just pry it out with a pic.

View attachment 862086View attachment 862087View attachment 862088

thanks Randy. Never checked or replaced the check valve on any of my counter vibes. Learn something every day. I think I’ll clean carb, set metering height and see if it starts. If not, guess I’ll order the check valve. I assume theY aren’t NLA.

 

[hotshot]

Walbro service manual is where I got the info, but check (pun intended) yours 1st as it may be fine, & yes those checks are still available.

That’s just one of several common HDB & HDC carb issues, as nozzle check “failures to seal“ won’t cause your dry plug, hard to start, nor a high speed issue...just a wonky idle.

 

[Maintenance supervisor]

The discs may “look“ OK, but can fail air testing. Here’s a pic of the tube at the nozzle, I use a piece of silicone tubing as it's more flexible.

View attachment 862085

This one “looked“ good, but failed vacuum as it was hardened up, so I just replaced it...comes as an assembly #86-523 so you don’t have to try to put the screen & that tiny midget clip back in.

Drilled & tapped thread #6-48 (same as rifle scope mounts), put in a short screw, & then levered it out. You could also just pry it out with a pic.

View attachment 862086View attachment 862087View attachment 862088

I use a blunted dry wall screw, on the sdc.