Poulan 3400 compression

[thomas72]

I have a low hour 3400 and just wondering what are the other compression ratio numbers on other saws being used by members at this forum. Mine is around 135psi, and trying to figure out if it needs rings. I have a 3700 Poulan but it has a thin ring piston and hits around 155psi, so it is hard to compare that to a 3400.

 

[FATGUY]

Even though that seems low, does it still run right? Any power issues? How low hours is it? If it's a fresh rebuild, maybe they haven't seated yet.....

 

[Brian S]

3400's traditionally have low compression. I rebuilt one a while back that topped out at 130-135. Ran great, another member has it now and reports good running.

There are some posts back in history here reporting same story and there is a guy on ebay that sells lots of good condition and refreshed 3400's and I've never seen any of his listed are more that mid 130's.

those are pretty solid saws, I miss mine some times.

 

[thomas72]

I do not know how many hours exactly are on it but the saw looks new, and the cylinder and piston look good as well. Its kind of strong with a 18" bar but when turned off hot and then restarted ten minutes later it does not want to start so easy as cold start. Carb seems to be adjusted right and plug is golden brown. If I can get some other compression reading from other saws to compare then I can figure out if the saw is really low on compression or it is manufactured that way.

 

[Modifiedmark]

I don't think you will see many with more than 135-140, thats where they seen to be. I have one in that range and all is fine with it.

All things being the same (cylinder chamber size) the larger bore of the 3700 should make a little more compression.

 

[Saw Dr.]

I have one at about 90 PSI if that makes you feel better......

 

[redunshee]

I don't think you will see many with more than 135-140, thats where they seen to be. I have one in that range and all is fine with it.

All things being the same (cylinder chamber size) the larger bore of the 3700 should make a little more compression.

I have several 3400's with compressions ranging from 120 to 135. All run great. One of them I bought new in the late 70's and its at 120 and runs like a bear. Put a little 2 cycle oil in cylinder and it only increased by 10 PSI. Unless its running poorly I wouldn't do anything. Not sure if new rings would increase it very much and unless it gets below 110 I'd let sleeping dogs lie.

 

[redunshee]

I do not know how many hours exactly are on it but the saw looks new, and the cylinder and piston look good as well. Its kind of strong with a 18" bar but when turned off hot and then restarted ten minutes later it does not want to start so easy as cold start. Carb seems to be adjusted right and plug is golden brown. If I can get some other compression reading from other saws to compare then I can figure out if the saw is really low on compression or it is manufactured that way.

Is it possible your vent line is plugged ?

 

[pyro2]

B200Driver: how does your Poulan 3400 run at 90psi? I have a 3400 that's 90psi on 3rd pull, 105psi on 5th pull. Saw seems to overheat after 3-4 minutes and eventually loses so much power it can barely run at all. Not sure what to do with it.

 

[Saw Dr.]

B200Driver: how does your Poulan 3400 run at 90psi? I have a 3400 that's 90psi on 3rd pull, 105psi on 5th pull. Saw seems to overheat after 3-4 minutes and eventually loses so much power it can barely run at all. Not sure what to do with it.

It doesn't. That was a joke. Those things seem to hover in the 130's for unmodded ones. That seems low to me, but they run good there, so who knows. At 90 PSI, I would be surprised to hear any piston port saw run. Reed valve ones will run with a little less compression.

 

[redunshee]

B200Driver: how does your Poulan 3400 run at 90psi? I have a 3400 that's 90psi on 3rd pull, 105psi on 5th pull. Saw seems to overheat after 3-4 minutes and eventually loses so much power it can barely run at all. Not sure what to do with it.

Remove cylinder and check, if okay re-ring piston and replace cylinder using a good sealant rather than a gasket. Should do the trick. As a second thought if saw is overheating I'd do a pressure and vacuum test to be sure seals aren't leaking.

 

[pyro2]

Can you define a pressure/vacuum test? I think you are referring to a test where you block off the exhaust and carb and pressure (or suck a vacuum) the cylinder to see if it holds. I don't understand how this tells you anything different than a compression test does. Do you use vac or pressure?

I understand how to replace the piston rings, but not sure about the cylinder gasket. I think you are also referring to the gasket under the cylinder where the 4 bolts are to remove the cylinder? Can you suggest a suitable sealant that can be removed later on?

I guess I'll start by opening it up to inspect the piston and cylinder and look for scoring. But for now I'm spending my effort on my Poulan 3700 for now. I have 3 saws, and 0 work reliably!

 

[lavs4x4]

Mine runs great at 120. Thought this was real low and needed a rebuild when I first got it but It seems to cut great and not lacking in power. How does your run? If it runs good I wouldn't bother pulling it apart.

 

[redunshee]

Can you define a pressure/vacuum test? I think you are referring to a test where you block off the exhaust and carb and pressure (or suck a vacuum) the cylinder to see if it holds. I don't understand how this tells you anything different than a compression test does. Do you use vac or pressure?

I understand how to replace the piston rings, but not sure about the cylinder gasket. I think you are also referring to the gasket under the cylinder where the 4 bolts are to remove the cylinder? Can you suggest a suitable sealant that can be removed later on?

I guess I'll start by opening it up to inspect the piston and cylinder and look for scoring. But for now I'm spending my effort on my Poulan 3700 for now. I have 3 saws, and 0 work reliably!

My reason for the pressure /vac test was only to see if you had an air leak or bad seals. I thought that the overheating over a period of time might result in ruining the seals. I normally use Dirko HT as a gasket sealant. Others use Yamabond or Permatex. Any will do so long as its oil and gas resistant.

 

[Guido Salvage]

I just came across this site as the 3400 I bought new in the mid 1980's quit running several weeks ago. I have never had a problem with the saw other then the starter going out (replaced it with one off a locked up 3400 I have).
In pulling the starter cord in the recent past I had noticed a lack of resistance, the compression test I just did (dry with no oil in the cylinder) confirmed it. After half a dozen pulls it barely got to 70 PSI. As I only paid $150 for the saw new and really don't need it, I hate to put any money into it. Based on what you guys are saying, it should not have even run prior to quitting.

 

[Mastermind]

B200Driver: how does your Poulan 3400 run at 90psi? I have a 3400 that's 90psi on 3rd pull, 105psi on 5th pull. Saw seems to overheat after 3-4 minutes and eventually loses so much power it can barely run at all. Not sure what to do with it.

As with all old and neglected chainsaws...you should (out of concern for this saw) send it to me for a bit of counciling and rehabilitation.

 

[redunshee]

I just came across this site as the 3400 I bought new in the mid 1980's quit running several weeks ago. I have never had a problem with the saw other then the starter going out (replaced it with one off a locked up 3400 I have).
In pulling the starter cord in the recent past I had noticed a lack of resistance, the compression test I just did (dry with no oil in the cylinder) confirmed it. After half a dozen pulls it barely got to 70 PSI. As I only paid $150 for the saw new and really don't need it, I hate to put any money into it. Based on what you guys are saying, it should not have even run prior to quitting.

Most won't start @70 psi. With a little work and not a lot of money your 3400 should purr. May only need a set of rings! Pull that jug and see how the P&C look.

 

[spudulike]

Just got hold of one of these Countervibe 3400 things - 100psi on the first pull and goes up to 125 - 135 on four pulls, I pulled out the base gasket and used a liquid gasket as I thought the original 125psi was low, had a couple of scored lines on the bore and got another 10psi but the thing runs fine, havent tested it out yet.

I agree with earlier posts, looks like these saws just have low compression as I am used to seeing 150psi - 175psi on the rest of my saw collection!

Spud

 

[Guido Salvage]

Most won't start @70 psi. With a little work and not a lot of money your 3400 should purr. May only need a set of rings! Pull that jug and see how the P&C look.

With nothing better to do today, I pulled the saw completely apart and started cleaning it up. There must have been at least a pound of oil and sawdust in every conceivable place!

After pulling the jug I immediately discovered the problem as the bottom ring fell out in two pieces. According to my local distributor, the rings and gaskets are no longer available. I see some on e-Bay, I will check for the best deal and get them ordered so I can put it back together.

 

[redunshee]

With nothing better to do today, I pulled the saw completely apart and started cleaning it up. There must have been at least a pound of oil and sawdust in every conceivable place!

After pulling the jug I immediately discovered the problem as the bottom ring fell out in two pieces. According to my local distributor, the rings and gaskets are no longer available. I see some on e-Bay, I will check for the best deal and get them ordered so I can put it back together.

Gaskets aren't available but I either make one or just use a good sealant like Dirko HT w/o a gasket. I believe rings are available. Part # is 530024332


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