I have a Weil McLain CG-6-spow boiler that won't fire. The pilot light is on, there is power to the trasnformer inside the boiler under the copper coil but no power comming out. I bypassed the aquastate, and all the other cut out devices and still no power. I am assuming it is the transformer but I don't know how to test it. Any suggestions of how to test this or what else the probelm can be

Simplest way would be with a meter ($15). Assuming that this is a step down transformer, the output will be an ac voltage, probably in the 24 volt range.