Chainsaw Symptoms

[mattcasdorph]

Ok, I have a feeling im going to catch flak for this. But I bought a chainsaw carb off eBay last November and used it on two different Poulan's. One was a P3816 and the other is a PP4218AVX since the carb was compatible with both. I can get them to idle pretty much. But when setting the H I get it to throttle pretty good but after cutting. Some it tries to bog down and ultimately dies. Why would it throttle properly at high throttle but die?

I hear a lot of people talking about buying genuine parts over Chinese garbage but money is an issue when everything is ridiculously expensive. The kits on ebay come with the carb, plug, fuel filter. I had some problems running it on the other saw before switching to the Poulan Pro. It had crap in the carb screen. I'm confused on what it actually is. Looks like applesauce. Not looking like gas varnish.
Got me thinking a out the fuel lines, maybe the chinese lines are deteriorating from the insides. Or perhaps the cheap chinese fuel filter. Maybe its breaking down and going through. I do have a Zama that came off the Poulan Pro but I'll likely have to buy a rebuild kit. But I cleaned this Chinese carb through and through. Even pulled the jets and shot compressed air through.

Just can't seem to figure it out. The carb was set the these specs.

L (1 Turn out)
H (2-1/4 Turn out)

I googled and AI told me Chinese carbs typically start out about 1-1/2 turns out on both. Is that accurate? I may be able to get video of how its acting.

Also would high compressed air had been enough to clear the jets? Or should I poke through it with a wire?

 

[MacAttack]

I have probably the same 42cc Poulan, I rebuilt the original carburetor with a Chinese made kit off eBay that worked fine. I have the Hi and Lo adjusters both at 2 full turns out. From what you described the gunk in the carburetor kind of sounds like the junk you get from ethanol gas that's been sitting.

As far as original vs eBay parts, I can at least speak for the PP4218 I'd be pretty shocked if the OEM carburetor wasn't made in China anyway.

 

[mattcasdorph]

I have probably the same 42cc Poulan, I rebuilt the original carburetor with a Chinese made kit off eBay that worked fine. I have the Hi and Lo adjusters both at 2 full turns out. From what you described the gunk in the carburetor kind of sounds like the junk you get from ethanol gas that's been sitting.

As far as original vs eBay parts, I can at least speak for the PP4218 I'd be pretty shocked if the OEM carburetor wasn't made in China anyway.

Thanks for the reply. Yeah the OEM Zama carburetor has China stamped into it..lol. I took it apart today to see what condition it was in and was pretty clean so I may put that back together and put it on tomorrow and set the jets to what you said and see how it runs. I removed it cause the buildup on the saw and wasn't clean I figured the carb was neglected too. (I bought the saw off Ebay too). The seller shipped it dirty..lol. So I just elected to swap the carbs off my other saw

 

[singinwoodwackr]

Ok, I have a feeling im going to catch flak for this. But I bought a chainsaw carb off eBay last November and used it on two different Poulan's. One was a P3816 and the other is a PP4218AVX since the carb was compatible with both. I can get them to idle pretty much. But when setting the H I get it to throttle pretty good but after cutting. Some it tries to bog down and ultimately dies. Why would it throttle properly at high throttle but die?

I hear a lot of people talking about buying genuine parts over Chinese garbage but money is an issue when everything is ridiculously expensive. The kits on ebay come with the carb, plug, fuel filter. I had some problems running it on the other saw before switching to the Poulan Pro. It had crap in the carb screen. I'm confused on what it actually is. Looks like applesauce. Not looking like gas varnish.
Got me thinking a out the fuel lines, maybe the chinese lines are deteriorating from the insides. Or perhaps the cheap chinese fuel filter. Maybe its breaking down and going through. I do have a Zama that came off the Poulan Pro but I'll likely have to buy a rebuild kit. But I cleaned this Chinese carb through and through. Even pulled the jets and shot compressed air through.

Just can't seem to figure it out. The carb was set the these specs.

L (1 Turn out)
H (2-1/4 Turn out)

I googled and AI told me Chinese carbs typically start out about 1-1/2 turns out on both. Is that accurate? I may be able to get video of how its acting.

Also would high compressed air had been enough to clear the jets? Or should I poke through it with a wire?

Try the low at 2 turns

 

[MacAttack]

Try the low at 2 turns

Yep, my PP4218 runs like garbage unless I have both needles at 2 full turns. It's not the easiest saw to tune, being a strato-charged engine. Mine runs pretty good though now.

 

[Michael E]

Thanks for the reply. Yeah the OEM Zama carburetor has China stamped into it..lol.

Zama is a company in China, owned by Stihl. They produce on another quality level as many knockoffs.

Cheap aftermarket carburetors often need different settings than what the saw manufacturers recommend as starting points. You may have to find your own settings from scratch.

 

[J D]

Also would high compressed air had been enough to clear the jets? Or should I poke through it with a wire?

Compressed air has a reasonable chance of destroying the nozzle check valve. If that's the case the carb is usually a write off. Poking wire through the jets can be equally problematic. Best bet is an ultrasonic cleaner or carb cleaner in a can

 

[stihltech]

Could it be something else wrong???

 

[Jay Hansen]

The fact that it runs ok initially but then begins to starve would seem to indicate that it's either not pumping or not metering enough fuel at wot. I'd check the tank vent first, if that's working properly, try raising the metering lever a tiny bit.