initially I thought it was to rich at the bottom.

I even tried the steps from the picco site
"Start leaning the low speed needle a little at a time (then repeat the reving up and idle test) and if it takes longer before the idle drops you are going in the right direction!
Eventually as you keep leaning with the low speed needle the idle will stay high, now it is time to lower the idle to get the desired low RPM. Finally richen the low speed needle half turn."

When I followed these step, I had to go in a lot on the bottom needle. Which made me think that it was to rich at the bottom, but I still had the same problem later in the day. I checked the tank seal and also change fuel lines before the last club race, but still had the same problem.