Sounds like you have the gaskets around the right way ,one way to test , is gravity feed the carby with some clear fuel hose that way you bypass the filter and if it runs ok like that you know the filter or primer has a problem.
Another way I test them is to fill a cup of two stroke fuel and connect a new primer to the clear line in the cup of fuel and with the other end connected to the carby then if it runs fine you know where the problem is.
