[Rob Doe]

Yes, the float valve could be leaking. There is an inexpensive external gauge that will let you determine this. The vendors sell them.

I had trouble on a thorough cleaning that I did. The main and cap jets were leaking at the bottom where they screwed in. I ordered Bratton's black washer kit and the problem was resolved. If you have a camera on your phone, you might be able to see this, but I stuck my middle finger into the carb and felt that the jets were dry at their tops but wet at the bottom. I then disassembled the carb halves and put the bottom on the bench and filled the bowl with fuel. It didn't take long to see the leaking jets.

I was reluctant to attempt to smooth the surface where the jets screwed in, but some use various methods to clean up that surface.

Good luck