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Poulan Pro PP5020 won't start

#1

virtual_guy

virtual_guy

My saw hasn't run for a while. The issues started when I was cutting up a fairly large hickory tree that fell. The saw started getting dieing after it got hot. Later it wouldn't start at all.

So here's what I've done and checked:

Changed the plug, fuel filter, air filter, carburetor, and ignition coil.

Low and high adjustments are about 1-1/2 turns from seated.

I occasionally get a single pop when I pull the cord.

The plug has spark, there is fuel on the plug when I take it out.

I don't have a way to check compression but it feels right.

I drained and replaced the fuel.

I pulled the fly wheel and the shear pin thing is intact.

Can anyone offer any advice?


#2

I

ILENGINE

Remove the spark plug and shine a light into the spark plug hole looking at the exhaust port with the piston in the down position. Any cylinder damage and you are done. Or you can remove the muffler but sometimes the mounting bolts will break off and look at the side of the piston, but the spark plug hole is easier


#3

virtual_guy

virtual_guy

Thank you. I'm ready to figure it out and fix it or throw the dang thing away. ? I appreciate anything I can look for at this point.

Any idea what might have caused cylinder damage if that's the case? I've taken pretty good care of it and it doesn't have that many hours.


#4

I

ILENGINE

If you find cylinder damage in that area most likely cause is running too lean causing lack of lubrication due to heat buildup. Fairly common with Poulan saws, or most low end consumer products. Modern emissions standards don't play nice with small engines.


#5

StarTech

StarTech

Poulan saws are not bad saws when properly tuned. The problem IL is very few techs even know how to properly tune a two cycle engine. Many techs are simply too lazy to even learn how.

The guessing at the carburetor settings of using the will start settings will get most techs in trouble. I have repaired quite a few two cycles and PNC damage is not all that common; unless, someone has pretty well straight fueled them or had improperly tuned them. It take tuning and actually using the saws during tuning process to get them right. This why I keep a log here at the shop and cut a lot of cookies.

And of course there is operators that have no idea of how to properly mix fuel or just buy the cheapest two cycle fuel oils. When a good quality multi mix oil is used fuel mix induced problems are rare in a properly tuned engine.

Btw going by feel on compression will not cut it as even with just 100 psi these engines will not start normally and even if they do they will not run right. 99% of two cycles require over 100 psi starting compression to even start.


#6

I

ILENGINE

@StarTech the issue with Poulan and most of the other box store handheld items are the carbs are set too lean from the factory and most people just live with it until it quit then complain that it didn't last long.


#7

StarTech

StarTech

ILENGINE said:
@StarTech the issue with Poulan and most of the other box store handheld items are the carbs are set too lean from the factory and most people just live with it until it quit then complain that it didn't last long.
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That might be the case as all I can only go by is what comes through my shop. Of the 50+ Poulans that came through my shop last year only one had PNC damage and that was because they stuck an cheap eBay carb on it. Now the MTD/Troybilt four cycle handhelds is a different, lots of PNC damage from lack of proper oiling which is a design problem.

After repairing the Ryobi backpack blower yesterday I can seen where they are set too lean but that could have been the Zama kit I used too. But I kinda doubt it. I actually surprised it didn't have problems other than the Ruixing needing a cleaning and new carb kit installed.


#8

virtual_guy

virtual_guy

Poulan saws are not bad saws when properly tuned. The problem IL is very few techs even know how to properly tune a two cycle engine. Many techs are simply too lazy to even learn how.
StarTech said:
Btw going by feel on compression will not cut it as even with just 100 psi these engines will not start normally and even if they do they will not run right. 99% of two cycles require over 100 psi starting compression to even start.
Click to expand...
Good info. This and everything else here in fact. Thank you all. I looked through the plug port and it looked "suspicious" so I took the exhaust off. I don't really know what that damage looks like but I'm pretty sure what I saw isn't good. I'm not in the mood to buy another saw but it's beginning to look like I'm about to do just that.


#9

virtual_guy

virtual_guy

PXL_20210323_165541661.jpg


#10

StarTech

StarTech

It been straight fueled and the PNC is now toast. Depending how much you want to put in it but it is rebuildable.


#11

Hammermechanicman

Hammermechanicman

Nice doorstop ya got there.


#12

virtual_guy

virtual_guy

StarTech said:
It been straight fueled and the PNC is now toast. Depending how much you want to put in it but it is rebuildable.
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I'm the only person who has ever put fuel in this saw and it has certainly always been mixed correctly. It may have been run lean, that I can't be so sure of. Would that cause the same damage? I'm not trying to debate your conclusion, just wanting to understand it.

Also, pardon my ignorance but what does "PNC" refer to?


#13

Hammermechanicman

Hammermechanicman

If your fuel mixture ratio was correct then either the saw ran lean for some reason or overheated or a combination of both. An air leak can cause it to run lean or a dull chain being forced into logs can overheat it. PNC piston and cylinder.


#14

I

ILENGINE

virtual_guy said:
I'm the only person who has ever put fuel in this saw and it has certainly always been mixed correctly. It may have been run lean, that I can't be so sure of. Would that cause the same damage? I'm not trying to debate your conclusion, just wanting to understand it.

Also, pardon my ignorance but what does "PNC" refer to?
Click to expand...
It has been my experience that a lean overheat situation normally scores the exhaust port area, but a straight gas run normally will damage the cylinder all the way around with some exception were the galling on the exhaust port pushes the piston into the intake side causing damage.


#15

B

bertsmobile1

other things that cause this type of wear are using starter fluid to start the engine
And running with too much oil that causes a carbon buildup around the port that breaks off & get stuck between the rings .


#16

virtual_guy

virtual_guy

So I'm the only person who has used this saw, started it, tuned it, or put fuel or bar oil in it. Unfortunately I think I know who's responsible. :LOL: My goal now is just to decide whether I want to rebuild or replace it. And to learn enough to not do it again.

I'll inspect it more carefully when I take it apart but I suspect I overheated it while cutting the fallen hickory tree I mentioned in the OP. It was a monster and while the chain was producing ok chips, it wasn't as sharp as it could have been by the time the saw died.

Live and learn. And thank all of you for helping me with the learning part.


#17

Hammermechanicman

Hammermechanicman

Had a guy bring me a stihl 251c that he tried to fell timber with like Paul Bunyan. Dulled the chain and just kept on cutting. Scored piston, burned up clutch, burned up clutch drum, seized clutch bearing, melted worm gear and melted plastic case around the clutch. $250 doorstop now.


#18

StarTech

StarTech

That like the guy that brought a walk behind from Tramlaw, put fuel in it and started mowing his lawn before he knew it there was a hole in the side of the engine. Never put oil in it until after the hole was in it.

Manufactures don't allow for the brainless operators in their designs. They are counting the operators that actually have a working brain and a little common sense.


#19

virtual_guy

virtual_guy

Hammermechanicman said:
Had a guy bring me a stihl 251c that he tried to fell timber with like Paul Bunyan. Dulled the chain and just kept on cutting. Scored piston, burned up clutch, burned up clutch drum, seized clutch bearing, melted worm gear and melted plastic case around the clutch. $250 doorstop now.
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Yikes. I don't see any visible sign of overheating (other than the piston of course) and didn't smell anything out of the ordinary (I'm assuming you would smell a burned up clutch). Is it still likely that I have damage beyond what a cylinder and piston kit will fix? I would like to rebuild this thing but don't want to head down a bad path.


#20

C

ccheatha

virtual_guy said:
Yikes. I don't see any visible sign of overheating (other than the piston of course) and didn't smell anything out of the ordinary (I'm assuming you would smell a burned up clutch). Is it still likely that I have damage beyond what a cylinder and piston kit will fix? I would like to rebuild this thing but don't want to head down a bad path.
Click to expand...
I took a Husqvarna I had to a local shop once. I had tried a 2-cycle mix that I didn't normally use and it was running lean. It got hot and bit the dust. One of the guys there took the plug out and shined a flashlight down the whole. He said, "dude your cylinder's scored. This thing is no good.". So I took it home. Was talking to a neighbor about it the next day. He told me that he'd dropped a tree on his (same model) and bent it all to heck. So he gave it to me. So I went to work disassembling the thing. Took the cylinder out and it was actually fine. Had a little oil streak on it, but that was about it. I figured it might be the magneto. So I replaced that with the one I now had for parts. I put it all back together again and it ran like a champ. When they do get to the point of shutting down after warming up, it can be a number of things. I like working on small engines, so I like the challenge, but sometimes it's not worth it. I like the Stihl I'm running now.


#21

D

Danz

Many, many, many years ago our logging crew would use the Poulan strictly in the cold winter months. We said a few nice things about Poulan because they cut like a Tasmanian devil. But that company had plumbed the exhaust underneath the fuel tank for the weather conditions on the Alaskan Islands and the cold Canadian forest. If the sun came out we lost all those saws because the fuel would boil. I imagine we detonated a few pistons etc when liquid fuel/oil boiled into the cylinder.


#22

D

dlutter

Probably too little too late for this thread but I used to have this saw and had a similar problem with keeping it running. I did a lot of reading about getting it tuned right. Had it running good with the L about 3 turns out and the H 2 to 2.5 turns out. I also ended up scoring the piston/chamber walls so it wouldn't hold compression.

This thread was helpful to me to read.

Poulan PP 5020AV Carb Carburetor Adjustment

Poulan PP 5020AV Carb Carburetor Adjustment
chainsawrepair.createaforum.com chainsawrepair.createaforum.com


#23

S

SlopeMan2

My saw had similar symtoms and the problem was a partly sheared crankshaft key. It would only pop when trying to start it. Sounds like is what yours was doing. It only took putting a new key. Good luck


#24

C

christophert

You will need to rebuild it. Most likely it was a lean condition (I deal with this often.) You can scout around for the parts and usually find a piston and jug for a decent price. When putting a carburetor on it, stay away from the Chinese knock-offs. I have had many issues with many of them (even causing engine failure!) Zama may be more costly, but in the long run the investment is worth it. I have a Craftsman 18"46cc (same engine as yours) and it is 21 years old. My only issue was with fuel lines and replacement of the original carburetor when I left my gas mix in it by mistake.


#25

J

jtk

ILENGINE said:
It has been my experience that a lean overheat situation normally scores the exhaust port area, but a straight gas run normally will damage the cylinder all the way around with some exception were the galling on the exhaust port pushes the piston into the intake side causing damage.
Click to expand...
I agree with the overheat. You mentioned it was a "big" log. If you had the saw close to the log for an extended period of time, the exhaust blows right back onto the saw and can over heat the piston and cylinder.


#26

C

cornwellkidd

StarTech said:
That like the guy that brought a walk behind from Tramlaw, put fuel in it and started mowing his lawn before he knew it there was a hole in the side of the engine. Never put oil in it until after the hole was in it.

Manufactures don't allow for the brainless operators in their designs. They are counting the operators that actually have a working brain and a little common sense.
Click to expand...


#27

C

cornwellkidd

Where a you or your shop. I have 4 saws the one I love is a little Poulan Micro 25 I use for trimming limes its so light no shops around don't want to look at it. I have not found a saw this light and easy to use


#28

J

Jetfan2207

I had the same symptoms with my 2001 Craftsman which I think is a rebadged Poulan. Take the cover off and prime it. Look for any fuel line leaks. My fuel line cracked so gas was just leaking out all over but I did not see it since the cover was on. It would start but only when cold but once you shut it off it would not start until cold again. When I took the cover off there were pools of gas by the lines but I could not tell where it was coming from. I was only able to see it when I used the primer and the gas was squirting out. IDK how but gas made its way into the cylinder and the plug was soaked. I pulled the plug out and left it out for a couple of days to dry out the plug and cylinder then replaced the cracked line (3 bucks at NAPA.) Replaced the line, reinstalled the dried out plug and filled it with gas and it runs perfect again. I was pricing out new ones and asked my neighbor who is a small engine mechanic on what I should get and he advised me to keep the old one going as long as possible and the newer saws are not made as well. This prompted me to look at it one more time which is when I found the bad line. If you do end up replacing the fuel line, replace all of the lines. I initially just replaced the cracked one but a month after it was back online the other line started to leak . Luckily I had enough spare line from the first repair so it saved me another trip to the store. Good luck!

Edit: just saw the photo of the cylinder. RIP saw.


#29

J

Joed756

An engine will tell you what's wrong most of the time. To run, and engine needs fuel, air and compression. If your compression has weakened you will blow blue smoke through the exhaust. If you weren't getting fuel your plug would dry. You haven't mentioned the air filter, so I'd take that out and try to fun it without... that just might be the problem. Put a new name brand plug in, make certain you have gapped it correctly. You can't see the strength of the spark with a tester.


#30

R

rushforth

I am a Poulan fan and have about ten + of the cheap saws - the Quality of the spark is important - clean flywheel and make sure the mag. is set right - (I use an alluminum can as a spacer gauge - check to make sure you have a good spark by pulling plug and spinning engine with plug attached and grounded. Strong blue white spark should be present. Often a new flywheel and mag will be needed and if you shop around you can get a kit cheap - about $15 - Also check that you crankshaft bearing does not have too much -or any play . -Good luck - don't throw it out but save it for parts! Usually these Poulans need the gas lines changed as well - if you cut a sliver off the end of the line then you can put the line in the hole - grab the remaining sliver with needlenose pliers and pull the gas line through - these gas lines are a common problem with most all saws - good luck to ya ! Rush


#31

VRR.DYNDNS>BIZ

VRR.DYNDNS>BIZ

ILENGINE said:
Remove the spark plug and shine a light into the spark plug hole looking at the exhaust port with the piston in the down position. Any cylinder damage and you are done. Or you can remove the muffler but sometimes the mounting bolts will break off and look at the side of the piston, but the spark plug hole is easier
Click to expand...
Also if the muffler is plugged no air flow/exhaust will flow thru. Also you say the compression feels right - but pull it over slow. If is has very little resistance the cylinder leakage is not good. At a slow pull the compression should not leak off overly significant, at a fast pull it will seem to have compression. The problem if slow pull leaks off is not so much compression but air fuel bypassing the rings back into the crankcase and having nothing to fire.


#32

B

bertsmobile1

rushforth said:
I am a Poulan fan and have about ten + of the cheap saws - the Quality of the spark is important - clean flywheel and make sure the mag. is set right - (I use an alluminum can as a spacer gauge - check to make sure you have a good spark by pulling plug and spinning engine with plug attached and grounded. Strong blue white spark should be present. Often a new flywheel and mag will be needed and if you shop around you can get a kit cheap - about $15 - Also check that you crankshaft bearing does not have too much -or any play . -Good luck - don't throw it out but save it for parts! Usually these Poulans need the gas lines changed as well - if you cut a sliver off the end of the line then you can put the line in the hole - grab the remaining sliver with needlenose pliers and pull the gas line through - these gas lines are a common problem with most all saws - good luck to ya !
Click to expand...

Please go to the attic , find the box with your old high school books in it and read the chapter on magnetism & electricity.
Magnetic flux is not effected by rust dirt oil grease or just about any other material sitting on the surface
Remember playing with iron filings a magnet and a sheet of paper.
On top of that mechanical work as in scrubbing with a wire brush will reduce the magnetism by altering the surface microstructure of the alloys used to make magnets.
All magnets loose their magnetism over time , it is called magnetic decay because being a magnet is a high energy state, remember the first law of thermodynamics ?
What is important is the gap between the magnet & the pick up as it affects the timing of the spark and the intensity


#33

B

bad69cat

Consumer grade saws have no cylinder liner.... so its raw aluminum. You MUST let them warm up at idle for awhile before going to full throttle! Otherwise the side of the cylinder closest to the exhaust valve heats up way faster than the other side and it scores the cylinder. If you warm them up first you can avoid the issue, even if it runs a bit lean..... but running a tad rich is always the way to go. You can get a compression tester for free at some parts stores (just a refunded deposit) if you want to do a quick test.


#34

B

Bellcrank

virtual_guy said:
My saw hasn't run for a while. The issues started when I was cutting up a fairly large hickory tree that fell. The saw started getting dieing after it got hot. Later it wouldn't start at all.

So here's what I've done and checked:

Changed the plug, fuel filter, air filter, carburetor, and ignition coil.

Low and high adjustments are about 1-1/2 turns from seated.

I occasionally get a single pop when I pull the cord.

The plug has spark, there is fuel on the plug when I take it out.

I don't have a way to check compression but it feels right.

I drained and replaced the fuel.

I pulled the fly wheel and the shear pin thing is intact.

Can anyone offer any advice?
Click to expand...
If the muffler bolts are frozen a quick test is use'n liquid compression. ( motor oil ) through the spark plug hole. Does not take much oil to fire a worn piston / cylinder combination.


#35

virtual_guy

virtual_guy

OK. I took this thing apart and replaced the cylinder, piston & ring. I followed a VERY good tutorial on the subject here:

>> tutorial video <<

So now I have replaced every fuel component but the tank, the plug, ignition coil, air filter, carb, cylinder, rings, piston.

It still will not fire once.

I looked at the plug when jumpered to the cylinder head and it has spark. It appears to be getting fuel.

So here's the only thing I can think of. In that video he runs a bead of gasket maker on the crank case where the shaft bearings seat (at 20:20 in the video). I failed to do that but I also noticed that there was none there when I took it apart. Is that a normal thing to do and could it be causing enough of an issue that it wouldn't hit at all?

Otherwise I'm at a loss.


#36

I

ILENGINE

You would think the rubber material around the bearings would seal those areas, but maybe they don't conform correctly causing an air leak. Did you put sealant on the mating surface around the cylinder base.


#37

virtual_guy

virtual_guy

ILENGINE said:
You would think the rubber material around the bearings would seal those areas, but maybe they don't conform correctly causing an air leak. Did you put sealant on the mating surface around the cylinder base.
Click to expand...
Yes I did. Loctite 515


#38

virtual_guy

virtual_guy

I picked up a tester and verified that I have plenty of compression (around 135 psi). I'm running out of ideas here.


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