1979 yz 125 carb issues

I am doing a winter rebuild on my 79 yz 125 and I am stuck. prior to rebuild fuel would slowly leak out of the overflow if i left the gas on. After rebuilding the top end i put everything back together and did my first heat cycle. The next day I went out to start it up, turned on the fuel, started kicking, and gas started pouring out of the overflow, both vents on the sides of the carb and exhaust port on the cylinder. I have already done everything as far as i know to fix it. took it apart multiple times adjusting the float height, brand new needle valve and seat. Held the floats under gas in a bowl to make sure they float and they floated right back up. hooked up the fuel line with the float bowl removed and lifted the float up. No fuel flowed when i raised the float arm. What else am i missing to fix this thing? its a Mikuni Carb