ORIGINAL: tinsink
Then can you substitute a diaphram that will work on the Zama?
If you have a problem with Zama, better substitute the whole carb

. If I remember right in this engine Poulan used C1U with 7 mm venturi. So you can easy replace it with relevant Walbro, 7 or 9mm. It will cost not much more than the ZAMA kit.