With the regulator you'll need a fuel pressure gauge to lower pressure. I know you said 8-12 psi but is that from a gauge in the fuel line? The other worse thing to do is start a car pull it out of the garage and shut it off. Even my modern fuel injected cars don't like it. When you start it run it till it warms up. What you did was essentially double choke the engine because choke was still on.