Poulan Countervibe 3400 "Fun"!

[seagiant]

Hi,
Got to look at my newly acquired Poulan 3400 and it will only start if I shoot a little fuel in the carb...

Then it runs for a few seconds and then cuts off.

That pointed me to fuel, so replaced, fuel line, filter and vent line. (Fuel lines were old anyway.)

No change, so pulled the carb, looks almost new or recently rebuilt.

Pressure tested carb at 7 PSI at fuel inlet and needle valve holds pressure.

I can see through the new fuel line it is pulling fuel but won't run.

I have ordered a new rebuild kit, but might just pull carb clean and put old parts back in unless anyone has something I am missing?

 

[ChillyB]

In my limited experience that little screen can be more clogged than it appears. Hold up to backlight next to a new screen.

Carb diaphragms are cheap, and are consumable items. I’d put a new kit in it and eliminate the carb as a question mark.

 

[seagiant]

In my limited experience that little screen can be more clogged than it appears. Hold up to backlight next to a new screen.

Carb diaphragms are cheap, and are consumable items. I’d put a new kit in it and eliminate the carb as a question mark.

Hi,
I think you are right, even though I can't find a problem with the pressure testing.

Just pulled the Carb apart, and sprayed everything with carb cleaner and put it back together with old parts.

Did a pressure water test and no bubbles.

Might be one of those things I can't see and hopefully a new Kit will get it going?

Just wondering if I have a massive air leak in the case/seals?

That will be my next step to test if the kit does not bring it around.

 

[seagiant]

Hi,
Ok, new carb kit, fuel lines, filter, vent line, spark is good, sort of lost on where to go next unless I buy a new OEM Carb???

Was trying to avoid that, I don't really think it is a big air leak or it would not run at all.

Carb is pulling fuel, can see that thru the new fuel line.

If anyone has any ideas, on what else to troubleshoot, I'm all ears!

 

[J D]

Did you set the metering height? Are the gaskets definitely the right way round? If you remove the adjustment needles & spray carb cleaner in them does it come out the jets & also into the metering chamber? Are the adjustment needles undamaged? How many turns out have you been setting it at?

 

[ChillyB]

Pull the plug, put on bottom dead center, invert, shake vigorously, let it sit with plug out and piston down for a while to air out. Maybe crankcase has a bunch of wet fuel in it?

 

[seagiant]

Did you set the metering height? Are the gaskets definitely the right way round? If you remove the adjustment needles & spray carb cleaner in them does it come out the jets & also into the metering chamber? Are the adjustment needles undamaged? How many turns out have you been setting it at?

Hi,
Thanks, yes metering height set and needles were pulled and sprayed all clear.

Needles look good, I run needles ooy about 1 1/4 turn out.

As I said saw will run but only for a few sec. and only if I squirt fuel in carb?

Carb seems to be pulling fuel, but where is it going?

I thought of getting a new carb just to rule a carb problem out but can not find one???

 

[Bob Hedgecutter]

It is about now I would be looking strongly at other culprits like compression or lack thereof.

 

[seagiant]

Hi,
Thanks, Saw was VERY dirty when I bought it.

Cleaned the outside just so I could handle it without getting oily.

Went ahead and pulled starter, removed coil (all covered in dirt and saw dust)...

Cleaned everything and tried again same deal.

Pulled spark plug hooked up compression tester and got 108.

Pulled muffler and piston looks great no scoring?

Isn't 108 a little low, for a chainsaw?

Oh yea, spark plug was wet, when I pulled it.

 

[ChillyB]

With wet plug I'd for sure shake out the crankcase and let it dry out.

 

[seagiant]

Hi,
Well, I saw where sometimes the fuel line can be to long, so I shortened my new fuel line and got it to run, but...

Could not keep it running without pulling the throttle.

It finally died out and now won't even burp, so I'm back to the carb or let it sit tonight and try in the morning.

I do think I finally made some headway with the fuel line problem, we shall see.

 

[slimbo3006]

Man reading this brings back PTSD of working on my 3400. I went through much of the same, I really wish I could remember specifically what was the culprit. (think I repressed those memories lol) I know it was definitely fuel related. IIR where the fuel line comes up through the tank to the carb is at an odd angle and mine had a kink/crease in it there that was restricting it. feel like I had to leave a little extra fuel line under the carb for slack to make it no kink. Seems like I might have had an alignment issue with the gasket under the carb on one as well. it was partially blocking the carb from getting a solid pulse.

Been my experience that these saws are notoriously hard to start anyhow. Mine runs like a champ but will not hit until the 10th or 11th pull almost every time it is cold

 

[9050LX]

Anyone been in the carb before?Mine would not run below about 4000rpm because prev. owner put in the wrong plate gasket.

 

[seagiant]

Hi,
I just rebuilt the carb so seems to be good.

I'll go at it tomorrow, but getting some good experience with this one!

 

[9050LX]

I have been known to screw down the cylinder cover over a longish fuel line before, pinching the fuel line.

 

[MHHPartner]

Mine starts first pull, but the oiler diaphragm is shot, so I can't use it. Too involved a repair to undertake for the foreseeable future - much more important pressing matters. Hopefully it will still run when I have time to fix the oiler.

 

[9050LX]

check the oil line, prob came off inside the oiltank from the filter.I suppose this saw also needs a healthy impulse from the crankcase to pump oil correctly, if gaskets aren't intact.

 

[dboyd351]

108 psi is low
most I have tested run 120-130 psi.
I think you will have a hard time getting it to run well at 108 psi

 

[seagiant]

108 psi is low
most I have tested run 120-130 psi.
I think you will have a hard time getting it to run well at 108 psi

Hi,
Thanks, well the piston looks great from the exhaust side.

Might need to just tear it down and if all good, replace the ring, and check the bearing/seals.

It still cuts out after just starting, It looks like the carbs are not made anymore, but I'm not that experienced with the older Poulans, admittedly!

 

[dboyd351]

Hi,
Thanks, well the piston looks great from the exhaust side.

Might need to just tear it down and if all good, replace the ring, and check the bearing/seals.

It still cuts out after just starting, It looks like the carbs are not made anymore, but I'm not that experienced with the older Poulans, admittedly!

Might want to pull the cylinder, scrub it with a scotchbrite pad, re-ring it, possibly do a gasket delete and put it back together.
I am definitely no expert on saw rebuilds but I have a number of 3400/3700/3800s and even one 5200 saw. Almost all the runners have 120-130 psi on my gauge and to my knowledge none of them have been rebuilt, so I am guessing 108 nay be a bit low to want to run.
Could also use your compression tester on other saws to see if it seems to give accurate results.
I doubt you really need a new carb. If you have access to an ultrasonic cleaner run the carb thru that and rebuild it.
3400s make great firewood saw. I love running mine.