Poulan 5020 issue

[orezok]

I have the above POS and it worked well for a couple of years. Always used can fuel, no ethanol. I live in the desert, so very few trees around here, but every once in a while. After it quit, I bought a Zama carb and it worked for a while again.

I gave up last year and bought a Makita electric as it does what I need once or twice a year on my 26 acres (NO trees other than Joshua Trees, and they are protected and won’t burn anyway).

I decided to get it running and sell it to the next sucker. I overnight soaked both carbs in a gallon of carb cleaner. Probed everything visible with a welding tip cleaner and reassembled. Got the factory “plumbing” diagram for the fuel lines and exploded views of the carbs to make sure flappers and gaskets were in the right place. Checked the float level to .012 below deck per factory.

By the way, I previously was an ASE mechanic and junior racer that built and tuned many 2 stroke engines. So I’m reasonably qualified.

Here’s the deal. A couple of pulls and it starts right up…. And runs for 2 seconds. Choke off and one pull and it starts again for 2 seconds. Repeat about 5 time while trying different needle settings and same result. Then nothing. If I pull the plug, it is soaked.

I don’t understand this one.

 

[nick 55]

Couple things to start with. Compression? Is the piston or cylinder scored? If not, what is your spark like? Is it a good color or just fizzle? Sounds like you have plenty of fuel, so if those check good, what is your baseline setting for carb tuning screws? Base idle screw? Will it stay running if you hold the trigger and try to start it like you would clearing out a flooded engine?

 

[orezok]

Compression is good. Lots of effort to them over, but I could do a compression test. Baseline has run the gamut of 3/4 turn to 2 turns. Same result at all settings. I built a jig that fits between the fins and can be turned with a drill motor. Tubing was sized to fit over the flywheel nut to center it. Spun the engine with plug out and full throttle for a minute or so and reassembled. Thought that the case might be totally saturated. No change. Spark looks to be average, decent blue.

 

[BLR]

Carb settings. Low 3 turns out. High 2-2.5 turns out.

 

[Burning man]

Pull the muffler off and check the piston, if it's is scuffed up bad just save your time and pass it on to someone else. If it looks ok set the carb screws and make sure the idle screw turned in, I hate tuning these saws because I've had leave it in fast idle then blipping the throttle as I tried to set the idle.

I don't know if anyone else has had my issue but on two zama carbs I've had the idle screw back out when cutting.

 

[heimannm]

I am not intimately familiar with the carburetor on the 5020 but is there a possibility in your probing with the torch tip cleaner that you punctured the high speed check valve? If so, the saw will flood out at low speeds, should run O.K. at wide open throttle if you can get it up to speed.

Mark

 

[Old2stroke]

Is that a PP5020? That would make it a strato engine and there would be two intake throats in the carb, one above the other. Strato engines are a bit different to tune, do a search on this forum on how to tune a strato engine. Lots of good info.
Do you have the right starting procedure? The throttle is latched partly open when you close the choke and stays open until you blip the trigger. This is the fast idle setting and must be set in this position for cold starting so when the engine fires with the choke on, just open the choke but DO NOT touch the trigger or you will unlatch the throttle. If you do unlatch the throttle, just pull the choke out and then push it back in to re-latch the throttle. It helps to turn the idle speed screw in one turn (not the L screw) so that when you get it running and blip the throttle to return to idle, the engine will be running quite fast and give you a chance to set the idle mix without it stalling all the time.

 

[RedneckChainsawRepair]

If original epa fuel line it will separate from lining and allow fines to pass by and clog screen inside carb. Just another thing to check.

 

[orezok]

Carb settings. Low 3 turns out. High 2-2.5 turns out.

When it last ran good, L was 3/4 H was 1 3/4. I live at 3500 MSL so that may be a factor. The fact that it is soaking the plug indicates over rich. I’m willing to give it a try at your settings.

 

[orezok]

I am not intimately familiar with the carburetor on the 5020 but is there a possibility in your probing with the torch tip cleaner that you punctured the high speed check valve? If so, the saw will flood out at low speeds, should run O.K. at wide open throttle if you can get it up to speed.

Mark

Yes, I might have screwed it up.

 

[orezok]

If original epa fuel line it will separate from lining and allow fines to pass by and clog screen inside carb. Just another thing to check.

View attachment 1038206View attachment 1038207View attachment 1038208

I replaced the fuel line a year ago or so as the outer line developed a hole right where it entered the tank. New filter at that time.

 

[orezok]

Pull the muffler off and check the piston, if it's is scuffed up bad just save your time and pass it on to someone else. If it looks ok set the carb screws and make sure the idle screw turned in, I hate tuning these saws because I've had leave it in fast idle then blipping the throttle as I tried to set the idle.

I don't know if anyone else has had my issue but on two zama carbs I've had the idle screw back out when cutting.

The piston looks perfect and compression is 90# plus.

 

[orezok]

Thank you everyone for your input. I’m going to continue monitoring this thread for additional info, but in the mean time i will order a new clone carb. I’ll update after replacement arrives.

 

[Gabriel1982]

Thank you everyone for your input. I’m going to continue monitoring this thread for additional info, but in the mean time i will order a new clone carb. I’ll update after replacement arrives.

Make it work ,sell it and try a Husqvarna . I would recommend Makita ,as I have an EA6100P but they are no longer manufactured! So Husqvarna would be my recommandation! Your problem could be carburation ,but also air leak from one of gaskets! If it sparks, doesn't wet the spark plug and runs well only when cold, it's an air leak! Clean the air filter too! I would say grab a 395XP but since you're "kind of" in a desert... Joshua trees don't need 395xp to "cut down"

 

[RedneckChainsawRepair]

When it last ran good, L was 3/4 H was 1 3/4. I live at 3500 MSL so that may be a factor. The fact that it is soaking the plug indicates over rich. I’m willing to give it a try at your settings.

My 5020 and locals 5020's I did was around this.

I kept adjusting the carb till I ended up with about 3 out on L from lightly seated and left 2-2.5 on H out from lightly seated at about 12.8K. Turned the I idle up too. Not like the 1 to 1.5 turns out we get used to.

Older and newer

 

[RedneckChainsawRepair]

The piston looks perfect and compression is 90# plus.

I like seeing 120psi min.

90 you sure you dont have a stuck ring?

 

[Junk Saw Collector]

I’ve read that a lot of the 5020’s run way better, more reliably, and eliminate the hot start problems with an intake mod. A couple of extra holes drilled in the plastic covers (inner and outer) over the air filter. There’s a couple of good YouTube videos on the mod.

 

[J D]

I agree with Redneck... 90 PSI isn't enough to reliably run. Either you're not using a small engine compression gauge or that's going to be part of the problem.
As it appears to be flooding another thing to check is pop off pressure... pump the carb fuel inlet up to 10-12 psi, it should hold indefinitely. If it leaks down the metering valve may be leaking & allowing excess fuel through.
As Mark noted, you may have also damaged the nozzle check valve... if the probing didn't, the carb cleaner may have as extended exposure to some cleaners will damage the diaphragm/check valve material. They also don't tend to like being blasted with compressed air

 

[Gabriel1982]

I’ve read that a lot of the 5020’s run way better, more reliably, and eliminate the hot start problems with an intake mod. A couple of extra holes drilled in the plastic covers (inner and outer) over the air filter. There’s a couple of good YouTube videos on the mod.

Even a new makita 6100 wasn't starting first pull this summer. But it was 38 degrees celcius in the shade, I was cutting 60-70cm diameter beech logs still green but no rotten cores at all. Full sun ,hard wood but still it would start 3-4 pull... Never worried about it...
I wouldn't drill holes in air filter cover if the manufacturer didn't design it that way!

If a 2 stroke chainsaw starts hard ,first thing I would look at is the compression,then spark to the plug ,lastly gasoline in the tank!
Things learned from about 23-25 years ago when I had a Cz-175 motorcycle! 2 stroke of course and made in 1956 (I think...).
Long gone now to a collector guy! Keeps it cleaner then I am

 

[leecopland]

The piston looks perfect and compression is 90# plus.

90psi is not great maybe rings are stuck if piston looks good