Move the filter in front of the pump. If its a mechanical pump the valves may not seat due to crud... you said there was a glass dome (aka pulsator) does it look like there is a fine white crusty looking coating in there? That's a sign that fuel and water have dried out and left the grit, and can affect pumping.
As mentioned... you need to look at your plugs. They will tell you exactly what's going on. Its one of two things... not enough or too much fuel. Are the manifolds tight? Is the heat riser working?
Before you rip out all the old.. hook up a vacuum gauge and pull the plugs.
