Bought a new Poulan Pro 5020 to see what there about

[bikemike]

To hear them tell it.....

The main thing with the V72 chain is to keep up with the rakers as you go, don't wait and have to take a bunch off at one time. If I have to take them down a lot at one time, a grinder makes real short work of it. A chain grinder that is not a belt sander or a 4" hand held..

I would much rather deal with the Oregon safety chain that comes on the 5020 then what comes on the homeowner Stihls..

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I have or had one of those. It's like taping a barbell on a saw

 

[LittleLebowski]

What would cause one of these to not be getting fuel? My fuel bulb isn't filling and the saw won't start. Yes, it's got oil and fuel.

 

[anumber1]

Fuel line broken, clogged, disconnected or otherwise.

 

[zogger]

What would cause one of these to not be getting fuel? My fuel bulb isn't filling and the saw won't start. Yes, it's got oil and fuel.

The hose is off the bulb itself, fell off or cracked, or the bulb itself is defective and leaks air or the fuel line from the tank to the carb is leaking air.. These air purge bulbs suck fuel up from the tank, filter end obviously, through the carb, to the bulb, extra mix goes back down to the tank with a shorter fuel line. Sometimes you can't see it but they get defective and leak a little and won't work. Best take the airbox/carb cover off, then the air filter, and take a look. You might be able to see what is up.

 

[TBS]

Could be a bad diaphragm or primer. Take the primer off hook two hoses up to it and try to pump some fuel through it in a cup.

 

[Chris-PA]

What would cause one of these to not be getting fuel? My fuel bulb isn't filling and the saw won't start. Yes, it's got oil and fuel.

Hot or cold start?

 

[LittleLebowski]

Hot or cold start?

It started dying during cutting today and I had to let it set for a while, then it would start. Now it won't at all (cold). Bulb isn't filling.

 

[Chris-PA]

It started dying during cutting today and I had to let it set for a while, then it would start. Now it won't at all (cold). Bulb isn't filling.

Air is entering the fuel system somewhere, either through a leak in a fuel line or in the carb itself. The Stihl (ZAMA) C1x carbs used on this saw are notorious for leaky check valves that can cause this.

 

[bikemike]

One thing I have noticed with new box store saws is they get test run and drained but I don't think they always use good gas. I have seen many new box store saws with hard fuel lines and carbs that didn't pump. New bulb, hose and kit it should be ok.

 

[LittleLebowski]

The fuel tank seems to be getting pressurized, it hisses when I open the cap after pressing the fuel bulb a few times.

 

[dgr]

Fuel goes through filter to one side of carb. It exits the carb to the primer bulb then goes from the primer to the top of the tank.

If you press on the bulb and it comes back out but doesn't fill with gas, the inlet line is sucking air or the line between bulb and carb has a leak. If you push the bulb and it stays depressed, there is likely a blockage in the inlet line.

You can also test the primer bulb by pulling the lines and covering the inlet and depressing it. It should stay depressed. Then test the outlet by covering it and you should feel pressure when you depress bulb.

Since it isn't fueling at all from your desciption, I would look at the filter and inlet line first.

 

[TBS]

I would bet the fuel cap vent is clogged actually causing a vacuum in the tank.

 

[LittleLebowski]

Now after it set for a couple hours, the fuel bulb works. Not new behavior. I won't have time to monkey around with this until Sunday. Thanks to all for the advice.

 

[zogger]

Now after it set for a couple hours, the fuel bulb works. Not new behavior. I won't have time to monkey around with this until Sunday. Thanks to all for the advice.

Still maybe running too lean? Gets hot, maybe vapor lock? Hmm. it shouldn't do what is happening.

It gets hard diagnosing and repairing over the typed page.

 

[TBS]

Saw stalls and primer will not pull fuel but after it sits bit the primer picks up fuel and saw starts then stalls again after a bit and will not restart and primer is not picking up fuel. The hiss was vacuum being released. When the fuel level drops a vacuum is generated causing the cap vent to open letting air in, if the cap vent is blocked a vacuum forms in the tank stopping fuel flow.

A good example of this is when you leave a sealed gas can sitting in the warm sun and see it expand and when it cools off the can looks like it got crushed.

 

[Chris-PA]

The hiss was vacuum being released.

It might have been, or it might have been pressure. The vent is supposed to let air in, but not out, so if the fuel warms during operation the tank can get pressurized.

The problem described could be a fuel system air leak, a blocked vent or vapor lock, which is why I asked if the problem happened hot or cold. The symptom still isn't clear to me - "dying while cutting " is quite different from "couldn't start", and it sounds like it's OK when first started.

 

[TBS]

The hiss occurs after pumping the primer a few times then opening the tank.

 

[Chris-PA]

The hiss occurs after pumping the primer a few times then opening the tank.

OK, I missed that. You still can't tell. The purge bulb/fuel line system is supposed to be a closed loop that pulls from the tank and returns to the tank, so it could not cause a pressure or vacuum in the tank regardless of the vent.

If there is a leak into the fuel system on either side of the bulb any pressure or vacuum the bulb tries to create in the tank will just vent out through the break anyway. But if the break is between the bulb outlet and the tank the bulb will fill and pump fuel all over the place.

If the vent is clogged the purge bulb will work and it will start and run after opening the tank lid, but will stop after the engine draws a vacuum.

If it's vapor lock the saw will start and run fine from cold, but if you stop it and let it sit a bit when hot the bulb won't work and it won't start, except maybe on full choke.

 

[LittleLebowski]

I really appreciate the replies and will troubleshoot tomorrow. I had to take a break from working on my property and take a mini vacation - an AK shooting class.

 

[LittleLebowski]

If it's vapor lock the saw will start and run fine from cold, but if you stop it and let it sit a bit when hot the bulb won't work and it won't start, except maybe on full choke.

This describes my malfunctions perfectly.