Pretty rare to have a PV leak anymore. Of it hot starts fine, it's not a blown PV.
Brown is too rich as well.
You need to read through the thread in the fuel and air systems with a title about power valve opening or something. 12many started it. Read it all. It has some really good pictures at the end.
You set your cruise A/F ratio by the main jet, and WOT with the holes behind the power valve.
All of that and more is in the other thread.
Did you make sure your water pump pulley is smaller that the crank pulley???