Check the power valve gaskets to make sure they are seal up against the metering plate correctly, it is very easy to get the gasket cocked, out of round, and make it leak I have done that I now install the power valve with the gasket holding the metering block with the jets pointed up so I can watch the gasket seat squarely agianst the sealing surface on the metering block Once you have it seated properly tighten it down well, not lightly