It is an enrichening circuit not a choke plate. The 'choke' bar pulls a plunger on the left of the carb on top on engine side. You should be able to see it. The plunger opens a direct circuit from the starting jet, sucking fuel vapor from carb bowl, to the engine intake.
The problem is that only the left carb allows the starter plunger be unscrewed. The rest of the carbs have to be taken out of the rack to have the room. Once the plunger is unscrewed, you can spray carb cleaner and see it coming out of the starter jet.
You should also check the floats are keeping level where it should in the bowls.
The problem is that only the left carb allows the starter plunger be unscrewed. The rest of the carbs have to be taken out of the rack to have the room. Once the plunger is unscrewed, you can spray carb cleaner and see it coming out of the starter jet.
You should also check the floats are keeping level where it should in the bowls.