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Poulan Pro 4218 chainsaw woes

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  • Poulan Pro 4218 chainsaw woes

    Quite a few years ago I bought a new Poulan Pro PP4218AVX chainsaw, with two chains, for probably not much more than $100. I also had a Homelite saw that I was able to get running long enough to do what I needed, and I also have an electric chainsaw that was fine for work close to the house, so I never even put fuel in the new saw until last year around this time, when I had to clean up some deadfalls up on the hill behind my house. I bought some pre-mixed 40:1 fuel and after following the starting instructions, it started pretty well and ran well once it was warmed up. I used it for an hour or so without problems:

    Later on, around the time I fixed the rusted seat belt anchor in my truck, I used it again for an hour or so to cut up some long-dead logs on a neighbor's property. Again, it worked OK. But it seemed to be harder to start than my previous saws when they were running properly. I went to use it again a while later, and it seemed to be even harder to start, and it seemed to bog down when trying to rev it up to speed. I think I left the fuel in it over the winter and finally around May I dumped most of the fuel and ran it dry, and stored it again over the summer.

    A couple days ago, I decided to tackle the deadfalls again. I added "fresh" fuel from one of the almost empty cans and another one that was full. It looked and smelled good. After a few tries, it finally started, and idled OK. It seemed to bog down but I had not let it warm up, so I went up the hill and got ready to do some cutting. Again, it was hard to start, seeming to require far more than the recommended 6 pushes of the primer bulb, but finally it ran. However, even after a few minutes warm-up, it still bogged down when trying to rev it up to full speed and it would not cut. I figured it was time to check a bit more thoroughly, and figured perhaps the air filter was dirty.

    I popped the cover and the air filter was still pure white and clean. I saw two access holes for the carburetor H and L adjustment, but they have external splines and no way to use a screwdriver to adjust. So I did some googling and found this video:

    It was for a very similar Poulan chainsaw with the same problem of bogging down. And he said it was a common problem, even after only a few hours use, and the solution was a simple carburetor adjustment for a richer mixture. I was able to make an adjustment tool using a piece of 1/4" copper tubing, and I was able to make some adjustments, but it was hard to tell if I was actually turning the screws with the cover on. Finally I pulled the cover off and used a flashlight and magnifier to make sure I adjusted both screws tight, and then back about two turns as recommended. After a couple more tries, it started and ran, and by adjusting the high screw out about 3-1/2 turns, it seemed to rev up to full speed nicely, and I was able to cut a couple of small logs before quitting for the evening.

    Yesterday, I was all confident and happy to be able to use my chainsaw to get back to the job at hand. So I expected it to start right up and I could get to work. But, no such luck. After several dozen attempts, still no joy. I gave it a break and tried again. Still nothing, just an occasional cough. I tightened the screws back to where it seemed to work the day before, and after a few pulls it ran and idled. But then it died, ne'er again to run.

    I pulled the plug (which was extremely tight), and it had something of a black oily finish. I cleaned it a bit and tried again, but still no go. This is getting very frustrating, and I'm tempted to just go out and get a "quality" saw, like a Stihl or Husquevarna, but it seems there is no reason this saw should not be able to run and meet my relatively minimal needs.

    I found some older threads on chainsaws, including one from Brian in 2009 where he had bought a similar saw and got a refund after threatening bodily harm to the store employees. I may dig deeper into my saw's innards and report on progress, or perhaps get something else. But I am a firm believer in proper troubleshooting, repair, and even modifications if something is not truly a lost cause. Any ideas? Thanks!
    Paul , P S Technology, Inc. and MrTibbs
    USA Maryland 21030

  • #2
    Katrina turned my place into a tangled mess of downed 100 foot pines. My ancient Homelite with a 16" bar was too small to cut through the big trees, and the only saw to be had in the area was a 20" Poulan Pro like yours. I fought with it for a couple of weeks, and did manage to get all the trees cut up. It ran pretty strong but was a bear to get it started.
    After Katrina, it sat for several months before needing it again, and then it started doing the same thing as yours. I tried all the tricks I could think of to get it running right but nothing worked. I even bought a tool to adjust those funny shaped carb screws. I finally gave up and took it to two different saw shops. That's two because the first one flatly refused to work on it saying he didn't work on junk. The second guy said he would work on it only if I paid up front, even though it was still under warranty. I'm not a 2 cycle expert but figured that it had to be getting air in the crankcase. I tore it down looking for cracks but didn't find any. However, when I removed the cylinder jug, I tore up the goofy shaped o ring gasket that seals the jug to the case. I ordered a gasket kit, and when it was all back together, the saw started right up and ran like a champ. I think that O ring must have been bad from the beginning, and got worse with age. You may have the same situation.
    Last edited by Dave C; 11-23-2016, 04:52 AM.
    “I know lots of people who are educated far beyond their intelligence”

    Lewis Grizzard


    • #3
      Here are some pictures of the inside of the chainsaw:

      This shows the splined LOW adjust screw:

      The cylinder head and spark plug:

      This is the tool I made from 1/4" copper tube. I had to crimp the end to make it fit well enough to work.

      I re-checked the adjustment and it seems that the low screw was only about 3/4 turn out, and the high was only about 2 turns. I think the tool had been slipping when I tried adjusting from outside. So tomorrow (well, later today) I'll try again.

      Meanwhile, I checked out some Husqvarnas, and they are about $300 and up to over $600. So I checked the local Craig's List. Here is a Homelite with a magnesium (maybe actually Zamak?) case like the one I bought around 1978 and served well until stolen in 1989.

      Or maybe one of these: ($75) ($75) (Small Husqvarna $150) (Stihl $250) (John Deere $200) (Stihl $175 50 miles away) (Husqvarna $250 50 miles away)

      There's also a new Oregon PowerNow 40V electric Li-Ion chainsaw nearby for $150:

      Might be good:
      (only 1.25 A-h, so at 40V, that's just 50 watt-hours. If saw is 1 HP, 750W, that's only 5 minutes of use!)
      Last edited by PStechPaul; 11-23-2016, 05:09 AM. Reason: electric saw
      Paul , P S Technology, Inc. and MrTibbs
      USA Maryland 21030


      • #4
        I have a Makita -Dolmar chainsaw that is a sod to start when its cold. So if I want to use it in the winter I have to leave it in the house overnight....then it starts first time.


        • #5
          I repair chainsaws frequently never seen one i couldn't get running.
          99% of the problems these days are fuel system related.

          1.Check compression if low it will be hard to start. bare minimum you need 100psi should be more.

          2.Check spark and flywheel key I have seen this model new with less than 5min run time shear the key

          3. Clean carb install carb kit new diaphragm etc...

          4. If it still won't run properly, check crankcase seal if the crankcase leaks from the cylinder base gasket or crank seals it will never run properly.



          • #6
            chainsaw, leafblower, weed cutter endless messages and threads about the problems just like the OP. It's No 3 every time. 1,2,4 are a bit more advanced. Just go for a No3. It is mostly dirt, more dirt, guey dirt, and small dirt. Undoing the screws sometimes is enough to move the dirt enough for a bit of a run, and sometimes using the thin tube on a can of carb cleaner down the hole you took the screw out of may be lucky, but if it is a bigger bit of dirt it may just blow it into the fine hole in the jet and get stuck needing a reverse blow.
            If it has a diaphragm they deteriorate with age just from sitting in the fuel. Also if you get a pattern part replacement do check the holes carefully. I replaced one this spring and it had a vital hole missing so hundreds of people must have been fitting these then finding it didn't help.


            • #7
              Originally posted by PStechPaul View Post

              ....... I'm tempted to just go out and get a "quality" saw, like a Stihl or Husquevarna, but it seems there is no reason this saw should not be able to run and meet my relatively minimal needs.
              I can't comment about Husquvarnas, but as for the Stihls ...I have a similar tale of woe.
              The first Stihl I bought was a model 011AV. It was a great saw ...many years of service.

              Then a few years back I bought a new Stihl model MS280. Sorriest piece of junk I've ever owned! ....except for maybe that crappy Stihl string weed trimmer hanging out in my shed!


              • #8
                Really no sense in blaming the brand if you did not take proper storage precautions as they all will act up if left to sit and build up varnish in the carb,

                also check all your fuel lines for cracking as the ethanol fuels will attack them, including your pulse line from the crank that powers the carb diaphragm/fuel pump.

                You might try to take a short cut, drain the tank and make sure you have good NEW fuel and premix - then add some sea-foam or the like - or maybe some chevron techtron, be careful easy to go way overboard and start chewing at your diaphragm gaskets and such - but - adding double or triple the amount will most likely be ok IF you run it all through at once and don't let it sit overnight or anything - this will attack the varnish and leave the rubber components alone for the most part...

                the fact that your saw acted ok before and then changed after "parked" should tell you something, what changed???

                the fact that you brought it around some with adjustment should also tell you something, you were simply compensating not fixing the real problemo...

                if you can get it to run at all then most likely means if it's a gum problem you can most likely clean it up with an additive...

                at least an alternative for those that don't know much about these little carbs and want to try to avoid tearing into them...


                • #9
                  In my case, a good portable generator and a good electric chain-saw solves most problems as regards "fuel".


                  • #10
                    Good luck with that Paul. I find that with most chainsaws, there is a certain level of sorcery involved in keeping the damn things running and starting right.----Brian
                    Brian Rupnow


                    • #11
                      What DaveC suggested in post #2 seems most likely the cause. Thanks!

                      I just now took the saw outside (about 42F), with the carb adjusted 1-1/2 LO and 2-1/2 HI, and after following the procedure of 6 pumps on the primer bulb and full choke, it started and ran for one or two seconds before dying again. No hint of starting after that.

                      This saw always has seemed to have "inconsistent" compression, where sometimes it would have a very "tight" spot when pulling on the rope, and other times it turned much more easily. And once in a while it would backfire and pull the starting handle from my grasp.

                      I have never had much luck repairing or even understanding two-stroke engines, especially newer ones in chainsaws and trimmers. Mostly, I'm sure it was due to stale fuel and carburetor dirt and glaze. I've also had problems with four-stroke lawnmower engines, again mostly newer ones, and usually because of carburetor problems causing the bowl to overflow and the engine would flood. I have two lawnmowers and three weed trimmers and one other chainsaw that need work. Plus a HF two-cycle generator that never ran well, and a really old generator that I got for cheap from a junkyard and I got it to run, but not well. It is possible that I had better luck years ago because of the fuel changes with ethanol. But I am using pre-mixed 2-cycle fuel for the chainsaw, and I think it is ethanol-free.

                      I have seen various videos and animations of two-cycle engines, and I think I understand mostly how they work. It may be that their inherent inefficiency compared to four stroke is what is hanging up my full comprehension. Here is one explanation:



                      I am really tempted to get the battery electric chain saw. I have a B&D battery electric weed trimmer that does a good job, and has served me well for probably 15 years, although I had to replace the (SLA) battery once, and it may need a new one again. Probably about $20. I also have a 120 VAC corded trimmer I bought for about $5 and it works great for the lawn within the 50 to 100 feet of extension cord from my house. And I also have an old (1970s) B&D two-blade electric mower that I worked on a bit and it's quite good within the limits of the power cord. I understand electric motors, love their simplicity and reliability, and their cleanliness and low noise level are wonderful as well.

                      I was somewhat put off by the 40V 1.25 A-h Oregon chainsaw because I figured 50 watt-hours would not give much cutting time. But I did a reality check based on the specifications, and perhaps it will be fine for my needs. The specs claim 125 cuts of 1" to 3" branches, which they say should average about 2 seconds per cut. The saw is probably about 1 HP, or 720 watts. Thus the 50 w-h battery should provide 50/720 = 0.07 hours or 250 seconds of use at that power. So that computes to the 125 cuts as claimed. It seems like 4 minutes of run time would be ridiculous, but for branch clearing (limbing) it is really quite adequate. And they have a model with twice the battery size (for $100 extra) that might be enough to cut the deadwood into perhaps four-foot sections that could be "coaxed" down the hill where I can use my corded electric saw to finish the job.

                      Another possibility is to use an automotive type inverter to obtain 120 (or 240) VAC from a 12V or 24V volt battery pack. I could drag my 100 A-h deep cycle battery (about 60 pounds) up the hill and run my corded saw through the inverter. If it's a universal motor, it might even run on my 1500W DC-DC converter I have mentioned before. The battery has about 1200 W-h, or about 20 times the energy of the battery chainsaw, and it should provide a solid one hour of run time at 720 watts.

                      I also have four 12V 12 A-h SLA batteries intended for one of my electric tractors, and they can provide about 600 W-h of energy from a total weight of 30-40 pounds. A few things to think about!

                      Thanks, and have a great "Thinksgiving"
                      Paul , P S Technology, Inc. and MrTibbs
                      USA Maryland 21030


                      • #12
                        I have a Poulan chainsaw similar to the OP's, bought it used for cheap money. My saw was hard to start and bogged when under load. I cleaned out the carb and got it to work fairly well. The nearest gas station to me, which is an "out in the country" hardware store (and also a Stihl dealer) has ethanol free gas. Since I have been using that gas and premium 2 stroke oil (Stihl or Echo in my case) my 2 stroke tools have run great even after sitting for months.
                        Using an ultrasonic cleaner on the carb is far and away the best method of cleaning all those tiny passageways.


                        • #13
                          I have a poulan also, bought it in-op for 25 bucks cuz the carb was gunked and the feed and fuel pump lines were cracked,

                          after an initial prime it usually starts first pull and then dies cuz it chokes itself out, then second pull with no choke and it's off and running,,,
                          I use ethanol shield synthetic 2 stroke oil from home depot, have had the saw for 3 years now and no problems, I do run it out of fuel end of wood season to store...


                          • #14
                            I heard back from the guy with the old Homelite saw for $100 and I might have a look at it tomorrow on my way to a Thanksgiving dinner.

                            But... I decided to give my saw another try, and I backed off the LO adjust to 2 turns out. First I tried it without priming, and it just barely seemed to catch but then seemed dead. JFF I checked the fuel, and it was only about half-full (or half-empty as you may). Shouldn't make any difference, but I added more fuel mix, shook the saw to get it mixed up, and tried again.

                            It seemed better, but still only ran a couple seconds. So I decided to "go ape" on the primer bulb and I pumped it maybe 15 times. It sounds like air bubbles are popping, but I also heard some more promising "squirt" sounds....

                            Lo, and behold, it started on the 2nd or 3rd pull, and after warming up a bit it even seemed to rev up to full speed. Yay! Of course, I don't expect it to start right up tomorrow when I try it again, but it's at least encouraging, and I may not need to spend $100 (or even $80) on an old (but perhaps better quality) chainsaw. It would probably be a "steal" if he'd take $60, but it's only been on the list for a few days. It may well be worth $80 and so if my saw seems like it may do the job for me, it may still be a good deal to have as a spare. He's only about 20 miles from me so I can go there anytime.

                            Thanks for the ideas and encouragement. I think it might be a problem with the primer pump and fuel system. I would think I would smell a lot of gas if it was actually squirting significant amounts of fuel with each push. It does look like there's an air bubble in the bulb, especially when I lay the saw on its side to pump it. Any way to bleed it, or check for fuel pumping into the carb?
                            Paul , P S Technology, Inc. and MrTibbs
                            USA Maryland 21030


                            • #15
                              the 4 digit poulan pros, ,4216,5020,3412, etc, are very problomatic, you either get a good one or a junker, usually the latter...the 3 digit Pros,, 210,222,260,320,440 and such are most always good saws, they have spring loaded handles f reduced vibration.usually a much improved saw.biggest problem is carbs are setup toooooo lean, and if run too long that way ,damaged piston is result, a slight richining up on the carb with do wonders for most chainsaws.most echos,poulans,sthils chainsaws, are very picky about a warm restart, must be done a certain way, or your arm will fall off trying ,, most all the swedish huskys are easy to restart warm or hot.
                              FORD BEATING JAP CRAP SINCE 1941!! CAROLYN JONES(1930-1983 actress)may this lady never be forgotten.