55 Wasp 202 Single Carter WAI-2009 Metering Rod

I rebuilt my carb with a Delta kit due to a leaky float needle. I took pictures snd made sketches. Upon assembly I notice that the metering rod is always in the retracted position with spring pressure from the aluminum plunger. I can see a wear mark on the top of the linkage tab that operates the rod/ plunger. I thought maybe someone had put the linkage tab on the wrong side of the throttle linkage pin that controls the rod. I tried moving the rod/plunger tab below the linkage pin and the operation seems correct, moving the rod up with throttle increase, but the rod will not down all of the way. I assembled the carb exactly how it was prior but I can see someone had had it apart before.

How is the metering rod controlled if it is assembled as it was originally so that the rod is normally open, does vacuum pull it down into the jet?

The top pic is how it was prior to dissasembly and the bottom pic is a representation of the tab pushing the linkage pin to hold the rod down at low speed.


  • KenU_Tx
    KenU_Tx Member

    YES, the vacuum piston pulls it down when engine is running at idle or steady cruising...when throttle is opened to accelerate, the vacuum drops, the spring pushes the piston up and raises the metering rod so that it's narrowest (richest) step is in the main jet for power.