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.

 

[Okie]

So the carb acts same on two different saws?????

From experience with those type Poulans: (some tips)
First you cannot just set the carb jets at a certain place and expect a good performance. the carbs has to be adjusted to the saw. THAT IS WHY THEY ARE ADJUSTABLE and why they usually do not perform correctly when not adjustable on old eq. When someone or the owners manual says to set the jet at a certain setting, this is only to maybe get the engine started.
If that is a strato type carb/engine they can be fineky. To adjust them I take the tuning tool to the woodlot log and first adjust the H jet for max rpms out of the cut then slightly back it out more (usually 1/4 turn or less) to the rich then slightly back in or CW. do not go any more CW than necessary or it can be lean and ruin the engine, then put the saw in the wood and test under load and make fine adjustments.
Next make sure the STRATO boot between the carb and engine is sealed good, not fitting loose or cracked. If it's not fitting good it will suck too much air and not run right due to the L jet not being correct. The strato butterfly is the top one on the carb and only opens allowing more air at 3/4 to max throttle. If the rubber boot leaks air at the lower rpms all tuning and running will be upset.

I've had good luck with the Hipa strato carbs from amazon (free returns if they don't operate good) with the metal strato lever instead of the plastic lever type. It's common for the plastic strato type lever breaks off quite often and no High strato operation. Sometimes the plastic piece at the intake has to be filed off to clear the strato lever at max throttle. (easy to do) Also make sure the primer bulb fuel lines are snug fitting. You have to be careful with the adjusting tool and you will strip the splines on the tool and/or the jet splines.
Here is the carb link with tune up kit at $16 free ship if you have Amazon Prime.
https://www.amazon.com/HIPA-C1M-W26C-545070601-Carburetor-Adjustment/dp/B079RKSMKW/ref=sr_1_2_sspa?adgrpid=1340305238691961&dib=eyJ2IjoiMSJ9.DQDDVxtDq5Bov8GOLRniDdAyg5iIWZbanLNaKc1fHSeyUmG-hFYoOZrbsg8CNix1Jnc21MT5bzw0TOO8B3COeNkGDdvsPN5vCZhqRzWD77oL2_z7BOZFTs9IBUO7_6XSygjg5IzRhAxr3YvB0aZWPyHtsXwanZtDPkgXKbH4PrHTtzlHXTFbXWjgRMoIrK4ZxON0LQR5MjNBcXWOE-EYrD1qGbcOGYhoWrpb57L8N0w.tYfumyA56B0wWzpf07gIZMB4PgOJW8Lgl7q5JyPkds8&dib_tag=se&hvadid=83769316509016&hvbmt=be&hvdev=c&hvlocphy=84572&hvnetw=o&hvqmt=e&hvtargid=kwd-83769425334422:loc-190&hydadcr=18650_13465103&keywords=poulan+p3816+chainsaw+carburetor&mcid=bd6c814a8e353cdfb4837a75a354005f&msclkid=7036c311969f1236db28a4df60d7d7ce&qid=1741616721&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

 

[mattcasdorph]

I wanted to come back to the post and thank you all for the help. Two turns out and its not bogging down at all now. Cuts really good now. I really appreciate the help

 

[Woodtroll]

I wanted to come back to the post and thank you all for the help. Two turns out and its not bogging down at all now. Cuts really good now. I really appreciate the help

It's great when folks let you know how something turned out (good or bad) so others can learn from it. Much appreciated, and glad it's running well!

 

[9050LX]

Yeah, I went over 2 turns out tuning one of these little Poulans. Funky ass little monsters to tune.

 

[mattcasdorph]

Crap. Back to square one. It's acting up again suddenly. I done cleaned the carb out the other day. May have to open it back up and see if its got gunk again.. It shouldn't but I'm having a issue with the primer getting stuck in and I'm thinking the fuel filter, but shouldn't be as it's new. That applesauce looking **** I was referring too. Wondering if its coming from that filter?? If it is and is coming through it may be clogging the carb. I also had that issue with the bulb sticking in on the other saw. Was using the cheap chinese filter that was supplied with the carb. I may make a bench test with the filter some line and a primer bulb and circulate gas a bunch of times to see if these filters actually are breaking down and causing sediment. If they do Im only buying OEM fuel filters from here on out. I just don't trust the quality of these that ship from china on ebay. I have a feeling the filters are breaking down and clogging.

 

[MacAttack]

Primer bulb collapsing is a sign you have a blockage / junk in your fuel system or carburetor.

 

[mattcasdorph]

Primer bulb collapsing is a sign you have a blockage / junk in your fuel system or carburetor.

Im going to take the carb apart again tomorrow and check it again. And let people know what I find out.

 

[dboyd351]

make real sure you have your primer bulb lines routed correctly
primer bulbs suck fuel from the carb and push it back into the tank
they do not force gas into the carb

 

[mattcasdorph]

make real sure you have your primer bulb lines routed correctly
primer bulbs suck fuel from the carb and push it back into the tank
they do not force gas into the carb

Filter line comes up to right side of carb and left side goes to inlet on the bulb and off the other and back to the tank. So it should be right.I believe it's a clog but where it suddenly came from I have no idea. Thats why I was suspecting the fuel filter. I ran brand new line. So it almost has to be the fuel filter itself or a clog in the carb somewhere. Actually I'm thinking I might bypass the carb completely and put the filter side directly to the primer and see if it sticks. If it does, its the filter. If it doesn't. I guess I'll be taking the carb apart again..lmao

 

[singinwoodwackr]

Pull all the lines and flush. The filter, if OE, is probably fine. If AM, they are a crap-shoot but usually ok. Flush out the primer bulb as well.
Disassemble the carb again and clean again. Don’t use carb cleaner on any rubber carb parts, gaskets, diaphragms.

 

[J D]

I acquired a saw a while back that had been sitting a while... flushed tank, replaced lines & filter, cleaned & kitted carb. Ran fine for half a tank then started acting up, some investigation led to me finding the filter was blocked. Wrote of filter as a dud & fitted another new one, ran saw & same thing again. Replacing the filter for the third time I found a ball of goo floating around in the fuel tank. Don't know exactly what it was but I'm guessing it was stuck inside the tank & didn't dislodge when I flushed it