46cc Plastic Poulan

[CTYank]

Chris, good write up and excellent result.
Chris and CTYank: Are the yellow 4218 Poulans as good, build-wise, as your 2775? Here are 2 on CL that I was considering getting to learn on.
http://huntsville.craigslist.org/tls/4576791847.html

Chris can take that one. What I can say is that the 4218 is a very competent worker, especially for $94. Not just me saying that here.

 

[Chris-PA]

Chris, good write up and excellent result.
Chris and CTYank: Are the yellow 4218 Poulans as good, build-wise, as your 2775? Here are 2 on CL that I was considering getting to learn on.
http://huntsville.craigslist.org/tls/4576791847.html

The saws in that add appear to be PP260's - they are 42cc and have a different engine design than the one in the 2775/PP295/PP4620. They run really well and also respond well to mods. That engine family went through a lot of mods over the years, with changes to the porting and compression, but eventually evolved into the strato engine in the PP4218. I have not run one of those but I'd like to. The addition of the strato system should have allowed them to make the port timing produce more power.

The PP260 is a nice saw - at that time the Poulan Pro models used a chromed bore, while the Poulan and Craftsman saws had a bare bore and chromed piston. I found a pristine PP260 engine and put it stock into my Craftsman chassis, with just a muffler mod. It's a great little saw, and sturdier than the 2775. I will always maintain one of those saws, as parts are so common and they work so well.

I lose track of who has what. Any chance that you've got some of the pistons and can weigh them for difference??
I always thought my 2900 superclean seemed to run decent, but mostly attributed the difference to the other peoples badly maintained chains.
Do you recall what carb is on your 4620? I believe this 2900 had a wt-285 on it.
Hate to say it but I've let things here get into a scrambled state over the last few years.

I beieve the WT-285 is what I'm running on that 2775. There were several model numbers used, but all the same size. You can look them up here (the 2775 is the P600 family): http://wem.walbro.com/walbro/category.asp?GroupName=Chain+Saw&FamilyName=POULAN

 

[Chris-PA]

Awesome write up Chris!!! I've been thinking about doing one on my Jonsered 2040 turbo. Its had the works; ported, welded pop-up, 6 degree timing advance and WT- 657 carb (thinned throttle & choke shafts and the casting flash as been removed,) the muffler is now just a hollow can with a 5/8 diameter pipe outlet.

It normally wears a 13" bar and 8 pin rim, its a limbing machine!!!!
last time I tached it in the cut it was pulling 11'700 !!!!

I absolutely love it!!!
View attachment 359929

Nice saw! I have one of those 40cc engines in my Husqvarna 142 (stock) and it runs very well. Like yous it has the same 13.49mm venturi as the 46cc saws, which is a lot of carb for a 40cc saw.

 

[zogger]

Chris, good write up and excellent result.
Chris and CTYank: Are the yellow 4218 Poulans as good, build-wise, as your 2775? Here are 2 on CL that I was considering getting to learn on.
http://huntsville.craigslist.org/tls/4576791847.html

I saw that ad, looked a decent deal to me.

 

[cedarshark]

Chris...I have a pp4218 that is in good shape but the piston and cyl are scored and need replaceing. Saw is only throwing 50 psi compression. I am familiar w/ Stihl clamshells but have never been into a poulan. Couple questions for you poulan experts:

1) can you clean up these cylinders that are chromed and how? I clean most nikasiled cylinders w/ a foredom grinder and emery cloth. Can you treat the poulan cyls the same way?

2) the 4218 IPL indicates a left and right "insert" at the bottom of the cylinder. What are these for and can you reuse them?

Thanks for your(and anyone else's) comments.

 

[redfin]

The inserts are the transfers. I have the same saw I'm rebuilding. I plan on using the same inserts because they are not damaged.

 

[cedarshark]

The inserts are the transfers. I have the same saw I'm rebuilding. I plan on using the same inserts because they are not damaged.

That makes sense..thanks Redfin.

 

[Chris-PA]

Chris...I have a pp4218 that is in good shape but the piston and cyl are scored and need replaceing. Saw is only throwing 50 psi compression. I am familiar w/ Stihl clamshells but have never been into a poulan. Couple questions for you poulan experts:

1) can you clean up these cylinders that are chromed and how? I clean most nikasiled cylinders w/ a foredom grinder and emery cloth. Can you treat the poulan cyls the same way?

2) the 4218 IPL indicates a left and right "insert" at the bottom of the cylinder. What are these for and can you reuse them?

Thanks for your(and anyone else's) comments.

You should be able to clean up the chromed bore the same way, provided the chrome is not damaged. I've cleaned up several.

I've never worked on one new enough to have those inserts, but I think they are a clever design. They effectively turn a simple open transfer casting into a closed transfer design. The piston doesn't really touch them so they should not wear out.

 

[cedarshark]

You should be able to clean up the chromed bore the same way, provided the chrome is not damaged. I've cleaned up several.

I've never worked on one new enough to have those inserts, but I think they are a clever design. They effectively turn a simple open transfer casting into a closed transfer design. The piston doesn't really touch them so they should not wear out.

Thanks Chris. Does the crankcase cap hold the transfer inserts in place? I have a tube of Dirko I use on Stihls. I assume this will work on a poulan?

 

[Benjie Duke]

I often read here about how big a saw one needs for, say, a 20" bar. Usually the consensus is considerably bigger than what I would say. I didn't have any appropriate logs to buck, but here is a video of noodling a 34" diameter white oak round, full bar. It's a cheap Poulan 46cc clamshell saw running a 20" bar with Oregon 20BPX chain:



View attachment 359875

These saws have been sold under many model numbers, as Poulan, Poulan Pro and Craftsman saws. There are also 36 and 40cc versions, some sold as Jonsereds (2036, 2040), and a few 49cc versions. They are very common, and are light (10.1lb powerhead) and decently powerful saws that respond well to a muffler mod. Unfortunately they have a couple of design defects that make them unreliable.

Mine is a 2001 Poulan 2775, a Type 1 with the early muffler and a chain brake. It's been pretty heavily modified by now, but not all of the mods are really required. First the defects and what I've done to fix them:

1. I got the saw from my Dad because it basically didn't work. The limiter caps made it so it would not run and could not be made to within the limits. I removed them. The fuel line didn't last much longer after that so it got replaced too.

2. The rear A/V spring mount is weak. The spring is mounted at a right angle, and the screws go into the plastic. I replaced one of them with a cap screw, and drilled a hole in the top of the handle so I could access it. I also added star washers to keep the screws from turning:
View attachment 359872
View attachment 359873

3. Next the rubber seal for the air box partition is a stupid design and they just come off. I tried gluing it on with Seal All and Yamabond4, but eventually used JB Weld:
View attachment 359874

Then there are the fun mods! The muffler is modded of course. The early Type 1 mufflers are really easy to modify, as the housing is two pieces. The internal baffle got drilled out, and the already large outlet was pried open. Here is a shot with the original baffle:
View attachment 359889
It was also ported, but it was before I had made a degree wheel so I was mostly winging it. The width of the ports is about 55% of the bore. This old shot of the exhaust is out of focus - I discarded the steel insert:
View attachment 359891
A better shot of the intake:
View attachment 359890
The ignition is advanced about 3deg. I tried to measure the port timing later through the spark plug hole and looking down the intake and got (duration):
E=158
I=168
T=115
But I'm not really sure I believe those numbers as it was not the most accurate view. I did not touch the transfers.

EDIT: I measured the numbers more accurately:
E=158
I=168
T=109

I really enjoyed reading this. But I'm not up on technical stuff. What exactly does those numbers mean. I know E and I mean exaust and intake. But that's all , is it measuring from what to where?
As I was reading I'm looking at 2008 pp4620 that I bought along with 40 or so for parts chainsaws. All of it was with it. It had a wrenchless clutch cover that I put a farmhand 2775 over replacing it. A 20" bar with a 7/32 3/8 chain, it was too big for the power it had. But another one in the bunch a 2001 Super Clean with 20" 325 chain. And it will pull that 20" 7/32. The difference in those two saws is night and day. I've had that particular saw a few times. None of them run like that 2001 does. You said that about the muffler shield. I'm looking at the 2008 and that shield looks good. So I check to the sc out. And it was broke off and it has no brake handle, looks like melted off. And where you said open transfers. Does that mean it's open instead of ports, referring to the crankcase and cylinder. And while I'm asking what is the technical name for the air head cylinder? Is it strata? I don't know is why I'm asking. Anyway I appreciate the read.

 

[Benjie Duke]

Then there are the fun mods! The muffler is modded of course. The early Type 1 mufflers are really easy to modify, as the housing is two pieces. The internal baffle got drilled out, and the already large outlet was pried open. Here is a shot with the original baffle:
View attachment 359889
It was also ported, but it was before I had made a degree wheel so I was mostly winging it. The width of the ports is about 55% of the bore. This old shot of the exhaust is out of focus - I discarded the steel insert:
View attachment 359891
A better shot of the intake:
View attachment 359890
The ignition is advanced about 3deg. I tried to measure the port timing later through the spark plug hole and looking down the intake and got (duration):
E=158
I=168
T=115
But I'm not really sure I believe those numbers as it was not the most accurate view. I did not touch the transfers.

EDIT: I measured the numbers more accurately:
E=158
I=168
T=109

So that's what a cheap 46cc saw can do, and what it takes to make one of these reliable. It's actually a very useful tool now, and given the weight it ends up coming out to work quite a bit. It's hard to justify putting a 20" bar on a larger, heavier saw when this runs as it does.

Do any of you know where the fuel tank vent is on the pp 4620? If it's the cap, they done a good job of hiding it.

 

[scottr]

Do any of you know where the fuel tank vent is on the pp 4620? If it's the cap, they done a good job of hiding it.

Yes , the center of the cap has a hole that leads to the duckbill valve .

 

[Benjie Duke]

Yes , the center of the cap has a hole that leads to the duckbill valve .

I know since 2001 the vent is in the cap of the 42cc and 50cc. I have a farmhand 2900 that is holding vacuum. I swapped out the caps, or I have 2 caps drawing vacuum, which only happens because it's mine.

 

[scottr]

I know since 2001 the vent is in the cap of the 42cc and 50cc. I have a farmhand 2900 that is holding vacuum. I swapped out the caps, or I have 2 caps drawing vacuum, which only happens because it's mine.

I had been working on a PP4218 and had that gas cap on my mind . My mistake .
The poulan 2900 and PP4620 use a different gas cap .
The IPL for the 2900 and the 4620 shows a valve and vent near the gas cap but not sure if it is for the gas tank or the oil tank .
I'll look at my 4620 and 295 after my breakfast .

 

[Chris-PA]

I really enjoyed reading this. But I'm not up on technical stuff. What exactly does those numbers mean. I know E and I mean exaust and intake. But that's all , is it measuring from what to where?
As I was reading I'm looking at 2008 pp4620 that I bought along with 40 or so for parts chainsaws. All of it was with it. It had a wrenchless clutch cover that I put a farmhand 2775 over replacing it. A 20" bar with a 7/32 3/8 chain, it was too big for the power it had. But another one in the bunch a 2001 Super Clean with 20" 325 chain. And it will pull that 20" 7/32. The difference in those two saws is night and day. I've had that particular saw a few times. None of them run like that 2001 does. You said that about the muffler shield. I'm looking at the 2008 and that shield looks good. So I check to the sc out. And it was broke off and it has no brake handle, looks like melted off. And where you said open transfers. Does that mean it's open instead of ports, referring to the crankcase and cylinder. And while I'm asking what is the technical name for the air head cylinder? Is it strata? I don't know is why I'm asking. Anyway I appreciate the read.

The E, I and T numbers are the duration the Exhaust, Intake and Transfer ports are open, in degrees of crankshaft rotation. Most people here quote port timing in degrees referenced to Top Dead Center (TDC) or Bottom Dead center (BDC), but this is an unnecessarily complication and requires one to find where TDC is. On a 2-stroke all ports open/close symmetrically about TDC, so all that is needed is to measure from when the port opens to when it closes, then if you want to know the timing relative to TDC you just divide by 2.

Transfer runners are the passages that go from the case to the side of the cylinder wall up towards the top of the cylinder - on simple castings these runners are formed with channels cast into the side of the cylinder wall, thus "open" to the cylinder. Essentially the side of the piston forms the other wall of the runner. More expensive castings have the passage formed as a complete tube that might run a better path.

The 46cc Poulans come with a 20" bar and 0.325" chain, which is generally too much, but if they are running well they can indeed pull it. It makes a very light, narrow and useful package. Sharp chain is a must and a muffler mod helps.

The fuel tank vent on the 46cc saws is under the plastic carb mount base. You have to remove the two screws that hold it to the case after removing the carb. Then there is a sintered bronze filter plug pressed in over top of the duck bill valve - I drill a small hole and pry it out. Sometimes I've reinstalled it with a little Yamabond4 in the hole I made. Sometimes I just put the plug back in with the hole to hold the duckbill valve in, and wedged some foam under the carb mount to hold it all in.

Strato is something else entirely, referring to newer saws that have an extra air-only intake and throttle plate in addition to the carb - at least sometimes. Other times it's a special carb and you can barely tell without looking at the cylinder.

 

[Chris-PA]

I had been working on a PP4218 and had that gas cap on my mind . My mistake .
The poulan 2900 and PP4620 use a different gas cap .
The IPL for the 2900 and the 4620 shows a valve and vent near the gas cap but not sure if it is for the gas tank or the oil tank .
I'll look at my 4620 and 295 after my breakfast .

Hi Scott - I hope you are doing well!

 

[scottr]

Hi Scott - I hope you are doing well!

Hey Chris , good to see ya posting .
I am well and socially distanced .

 

[Chris-PA]

Hey Chris , good to see ya posting .
I am well and socially distanced .

It's cold today and I'm being a wuss, sitting by the little stove and wasting time on the laptop. I guess you'll have that from time to time!

We sure needed more social distance, huh? As if people didn't spend enough time with their faces glued to a screen, and unable to interact personally.