When setting with a Choke and it has a High speed idle control Like most carbs do Only one choke should? be needed to Hold for the High Idle.
Two things a choke does
1) it sets restricts air flow But increases fuel
mix.
2) it sets and Holds high idle till the motor is
warm enough to run on it's own. Then the choke is now wide open.
So my 2cents is That if you choke all 3 carbs You will then be dumping in Way to fuel to air and could very well end up floading the motor.
What i have done in the past for a choke less set-up is richen the fuel mix up for cold weather. This really depends on just how cold it gets on how well it works. But a choke is the better way to go.
God doesn't like ugly.
