40 year old Poulan 3400 that has never run right...

[Comprodigy]

For the entire time my dad has owned this saw, he says he couldn’t keep it running. It’ll start, but then bog out, some times I can keep it running by goosing the gas, but it always dies at some point. Then I can restart it and run it again. From research and some tear down I can see it needs a MM and a different filter system for air intake, but the main culprit seem best described by a vacuum in the gas tank. So I checked the vent line, AND THERE WAS A SCREW IN IT!

Now in looking the rest of the saw over, the bar needs work. It needs the rails sanded or filed, and in a couple parts they are splayed out, if that’s the right term. They are to wide. What can I use to close this gap, without going to far, to fix this bar?

(By the way there aren’t any flat spots, which is amazing for it still being the original bar!)


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[brandonstclair20]

There is supposed to be a rubber duckbill valve in the tank vent. That may be a lot of your problem.


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[Wagnerwerks]

The screw was outside the tank in the vent line? If so, that's normal. It's also common for many other brands. I always used homelite vents. If it boggs from cold like that its adjustment or fuel supply, not the vent. Check inside the carb for dirt in the screen. The air filters in them are actually not bad if the flocking is still there. The foam that seals the filter in is usually the issue as it gets worn and allows dirt by. The muffler on that saw breathes pretty well for the 3400s but an extra slit cut in behind the old one and some prying with a screwdriver works well to open it up. Then just drill the baffle holes out one or two sizes.

 

[Comprodigy]

There was no valve in the line... and it bogs down even when hot. The hotter the harder it bogs down, and the harder to keep running. The way I see everyone online set up the vent hose is to just put another gas line filter on the end of it outside the tank and run it that way, that’s why I was surprised to see the screw. The gas flows freely through the lines to the carb, and the carb is clean. The way the air filter was that was in it, it was only breathing through a spot the size of the carb intake, not the whole filter. Thus why I was thinking of redoing the air filter system.

On the muffler, the port dumps into a rectangle shaped baffle with holes in it and spark screen wrapped around it, then the only exit was holes in the back pointed at the engine cylinder, but there is a cover plate that turns the exhaust to come towards the front/bar side of the saw. A very restrictive setup. So I drilled four 1/4” holes in the front of the muffler behind the cover plate that is on it and then five 1/8” holes in the cover plate spaced to allow some of the exhaust to flow from the larger holes directly out, but still redirect some of it to flow out the sides of the cover. Without any adjustment to the carb it already seems to be doing better when I run it. No notable increase in sound ether.

As for the bar, the chain is also near the end of its life so I’m going to go to the Stihl dealer in town to see if they have a replacement for both that fits. But if anyone has a recommendation on what 20” or 24” bar to put on, I’m open to suggestions.

Thanks for the feedback! Please keep it coming! Only way I learn is if someone has a better idea.


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[Scotty Overkill]

years ago, I bought a MINT McCulloch Pro Mac 610 off a guy, he said he bought it from the original owner, who told him he couldn't get it to run right from near-new. I took a chance on it for 40 bucks, and it suffered similar issues to what your Poo-lan does.

I got a carb kit, tore the carb down and cleaned it, rebuilt it and STILL ran like shiznit. So I went out to my shop and found another Pro Mac carb, put it on the saw, and it ran perfect.

I'm thinking that the original carb had internal issues (possibly a dicked-up venturi?) that, no matter what you did to it, wouldn't allow it to tune properly.

So, if all esle fails, try another carburetor. But first, check for fuel line problems, clogged filters, plugged-up or broken impulse line/circuit, etc. Rule out the simple stuff first.

 

[Wagnerwerks]

Right on. I bet internal issues with the carb too. I think i have carbs if you need one.

 

[Comprodigy]

Thanks, I have been thinking about replacing it, I played with the idea of trying to rebuild it but I think it’ll be better to replace it. I’ll PM you about cost.


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[Comprodigy]

Oh and from what I can see, there is no impulse line coming out of the carb. I do need to open the carb to see if there is anything obvious...


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[Scotty Overkill]

Oh and from what I can see, there is no impulse line coming out of the carb. I do need to open the carb to see if there is anything obvious...


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It's probably an internal impulse curcuit, thought the carb base.

 

[Comprodigy]

Could be... I wouldn’t know, or know what to look for.


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[Scotty Overkill]

Could be... I wouldn’t know, or know what to look for.


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Look at your carburetor gasket, there will be the big intake hole, the mouting screw holes on either side of that, and then a smaller hole somewhere off to the bottom or top of the intake hole. That's your impulse hole. That's what supplies the crankcase vacuum to the fuel pump diaphragm in your carburetor.

Sometime's that hole isn't aligned properly with the carb or the intake base, and can affect fuel pump function.

 

[Comprodigy]

Found it in the diagram. Thanks! I’ll look at that next.


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[Wagnerwerks]

It's through the carb base and intake on that saw.

 

[Comprodigy]

Well I got feeling worse today, so did get to spend the time I wanted to on this saw... and when I first looked at this bar, I just glanced over it because that was not my main concern. No flat spots to speed of... but it is pretty beat up. I think if I file it it’ll be ok. I don’t have the proper setup to grind or sand it. But then I’ll have to close the guides, because they are open and not holding the chain right in places. Any suggestions on how to close it? Without buying a special tool?


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[Wagnerwerks]

To close your bar, insert a sawzall blade in the slot and gingerly hammer it shut on an anvil or something similar. The blade keeps it from getting too tight. A little can go a long way so go slow and even.

Another option...depending on what size bar you want... I could send you one with the carb.

 

[Comprodigy]

The only bar that I know will be tough that I have found is the Oregon power-match and this saw came with a 20”, but from what I read that’s the max it could possibly handle.... and I don’t want to go smaller. So I’ll stick with a 20”, but the best $ I’ve found so far is about $55 on Amazon. Can you PM me a $ one just the carb and the other for the carb and bar? Thanks.


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[Comprodigy]

The saw still has some parts off it, I’ll post a couple pics soon of the bar, found out it’s the original bar from the factory. My dad has never changed it! So I’ve been trying to dress up the edge a lil so it doesn’t look like it was chewed on. The entire saw is in pretty good shape for a 40 year old saw!


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[Comprodigy]

Ok this saw runs real nice! But... I can’t get it to idle right. I have to give it a lite squeeze on the trigger to keep it running. So I think there is an issue with the carb somewhere. Plus I noticed some exhaust coming out the carb intake when it would die. It’s not bogging out like it was, just seems to now not be getting fuel like it should. Any suggestions on tuning the carb?


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