Not to sound antagonistic, but any carb that only requires more than .5 psi to hold the needle off its seat is in my book a bad carb. All the automotive carbs I have ever dealt with can stand anywhere from 3 to 7 psi without flooding, provided the needle and seat is in good condition. Most mechanical pump will make 3 to 5 psi in stock form. Being able to run at .5 psi, and maxing out at .5 psi are 2 different things. I think that if I had a carb that I knew could not withstand more than 1 psi, I would junk it and find another one. Just my opinion. I may find this Zenith ends up the same way and I go looking also...
Colin & Bev Rainey KR2(td) crain...@cfl.rr.com http://kr-builder.org/Colin/index.html Sanford, Florida KR Gathering 2004-see ya in Mt Vernon