Hi Jody,
I have ZS's on my TCS Europa, and have the dial regulator too, made by a reputable firm, not the cheapie type, but never had a problem with it. I checked pressure from it upon installation, and it matched the dial. But check it just in case.
I had trouble at one time with Grose Jets sticking closed as I didn't wash them in acetone before installing them. As a second check, pull the diaphrams/pistons out and see if you can see the gas near the top of the needle jet. As Dr Entropy said, check the diaphrams, and I am running 2.5 psi on my ZS's, works great.
I had trouble starting my TC a while ago, and had to pull the starter to ensure it was cranking fast enough. Once I overhauled that, it seemed to start easier. FWIW, I also installed a starting circuit (choke) on the rear carb, and a CD ignition which also helped it to start when cold.
I hope this helps, Jerry