cannot get poulan 4218avx to run with power

[r7000]

given to me was a 4218avx, pretty sure brand new maybe used once for 10 minutes.
I recently replaced the fuel line in the tank, where the filter connected to the line in the tank the line rotted and filter fell off. Was able to feed some tygon line and everything is now good regarding fuel lines, tank cleanliness, and fuel filter. And I replaced the original torch spark plug with a ngk bpmr7a.
I have pulled the carb numerous times and blown it out with brake cleaner and compressed air.

It'll start right up but I cannot get it to idle "steady" at ~2500 rpm.

If I crank out the Lo mixture needle the rpm's will go up to 4000-5000.

But even as I am able to get it running < 5000 rpm, if I give it throttle it'll die. If I feather it I can get rpms > 10,000 to the speed one would expect, but there is no power... with a chain trying to cut it'll just bllaaaa and stall under load.

What else can I try doing at this point?
And what would be the ballpark number of turns out on the mixture screws? It seems like I need at leat 2.5 turns out right now. The carb is a Zama W26

 

[AVB]

I personally I never heard of anyone using brake cleaner on these carbs. Here I only use soap and water in my ultrasonic cleaner to clean any 2 cycle carburetor. Plus I never use high pressure compressed air on these either as there are tiny check valves that be easily damaged.

With you disassembling the carburetor and using both the brake cleaner and compressed. You got remove the airhead which will require a new gasket as well as all the other carburetor gaskets and diaphragms. The base will start mixture settings are 1-1/2 turns on each with finial tuning the H will be out more turns depending on the saw's engine condition.

Also note these saw using airheads can damage the cylinder from being too lean.

With what you have done to the carburetor I would getting a new carburetor and start over. But before doing that check the engine compression and if it is below 100 psi you will also need to replace the piston and cylinder.

 

[Husky268]

AVB is right you probably have blown a check valve out, but i would pull muffler check for scoring if there is none then take a small screwdriver and push on the rings and see if they are stuck if that is good then buy a new carb they are cheap.

 

[67L36Driver]

If it ran any at all with the fuel filter off, it will have sucked up enuf trash to plug the carb’s internal fuel filter screen.

Those ‘two barrel’ setups are extremely hard to adjust correctly. [emoji2959]

I avoid those like the plague.

 

[AVB]

Yes it might be one of those filter screens that you can't tell visually if it is plugged or not.

Not a problem to tune here but it may be that I have work quite a few of them. Now they do need tuning richer than normal due to the additional air being supplied. I personally own one of these Poulans that I upgraded to a NCC cylinder from where the previous tried tuning the carb and ruin the non-plated cylinder. Now it was the $130 version of the 4218AV instead the more expensive $180 version.

The 4218AVX does use the the non-plated cylinder and should be upgraded to the NCC Cylinder and non plated piston.

The tuning just takes experience with these airheads.

 

[Husky268]

I work on these everyday its always straight gas, carbon or bad carb or clean carb. on that carb the trash will be on top of the screen and not below,below will be on the walbro wyk's wyl's & so on type carbs.check cyl and ring if not that buy a carb.