Rebuilding a carb for pollan pro 445 walbro carb need to know when replacing the diaphragm which way the round metal goes facing outward to inward tks gene
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You rebuilt the carb? could the metering diaphragm be installed upside down? (THE ONE WITH THE DISC) or could it be the lever connected to the needle isn't set to correct height? Zama and Walbro have great web sites. one more thing are you sure you put the fuel lines (2) on the right spot?? one line goes to the filter the other is simply a return and only goes in the tank but not too deep into the fuel
The gaskets and the pliable diaphragms in the carb have dried out. Therefore, the carb cannot deliver fuel to the engine. Disassembly and cleaning of the carb will be required (esp. if very old fuel left to dry inside it). After that, a rebuild kit or at the least; a gasket and diaphragm kit will need to be installed. This will then enable fuel to get to the engine. If you repost the exact model number of this machine, I can reply with the part number for a rebuild or gasket and diaphragm kit. Your unit has probably a Zama (will be wrote on the cover with vent-hole) or Walbro carburetor. Kits are available for both.
You probably know that it may need a rebuild kit with the new gaskets and diaphragms in it. It is quite possible a kit exists for it even though it is antique. Is it a Walbro or a Zama? I will send you to a tutorial by Zama on tuning a 2 stroke carb which includes your mixture screw settings. If you need help finding a rebuild kit or just a gasket w/diaphragms kit, please post back. I will be glad to assist.
My best guess is that you replaced the internal parts of the carb, but you did not clean it and adjust it well enough. Take the carb back off and clean out all of the passages with aerosol carb cleaner. Remove each of the adjustment screws and blow cleaner through them as well. Reset them by turning them gently clockwise until they seat, then turn counterclockwise 1.5 turns each. This is a good starting point. Make sure the needle arm in the carb is set at the correct height. If you have a Zama carb, you can use a straight edge to set the height. Lay the edge across the carb (where the diaphragm will be) and check to see that the needle arm is just even with the edges of the carb.. If you have a Walbro carb, you will need to get the Walbro tool (WB 500-13-1) to get the needle arm set to its proper height. An arm that is set too low, will starve the engine and one that is too high will flood it. Also make sure the gaskets are installed in the proper order. Diaphragm side, the gasket goes on first, then the diaphragm. On the metering plate side, the metering pump goes on first (thinner one) then the gasket goes on, then the outer plate.
Don't forget to replace the inlet strainer (small screen).
On to fuel lines. You Weedeater product uses 2 sizes of fuel line. The smaller line must connect to the fuel filter in the tank, and then to the fuel port on the carb that is opposite the diaphragm. The fuel port that is closest to the diaphragm will connect the larger line. This is a return line and will go back to the tank. It may or may not have a small fitting on the end of it in the tank.
Now try a test run again. If it will idle, but not rev up, open up the Lo adjustment screw (closest to the engine) by turning it counterclockwise 1/4 turn. Test run. No change? go another 1/4 turn. If after all this, it is still not running properly, then there is a fault in the carb and it will need to be replaced.
The problem centers around the carburetor. The question lies in the condition and operation of the carb initially.
It appears you may need to double check your assembly of diaphragms and gaskets. check for loose welch plugs, adjustment needles in the wrong holes, inlet needle set too high.
*note: metering side diaphragm goes on top of the gasket, fuel pump diahragm has the gasket on top of it.
It is either a Walbro or a Zama carb. I think both mfrgs have a website w/ parts breakdowns. But both carbs are the same as to the placement of diaphragms + gaskets. On the side with the inlet needle the gasket goes on first and then the metering diaphragm. On the fuel pump side the diaphragm goes against the carb body and then the gasket before the cover.
I have seen 2 different carburetors used on this unit. A Walbro and a Zama. You will need to get the information off the carb. (Walbro WYC-10 or Zama K39A) are the two I have seen, but you need to be sure what yours is. Then purchase the correct O/H kit and rebuild it.
HDC carb 
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