Rochester B Two Stage Power Valve

2stage_power_valveThe two-step power system provides better fuel distribution at the top end of the cruising range where slight enrichment is normally required. It performs this function by the use of a new type power valve assembly. Looking at the illustration, note that the power ball slightly off of its seat, (as it will normally be at the upper end of the vehicles cruising speed), the clearance between the ball and the power valve well is very little and actually controls and meters the power fuel flow. However, at wide open throttle, when full enrichment is required, the ball is moved out and past the restricted well area, at which time the regular power restrictions, pressed into the well support assembly, controls the power fuel requirements. This power valve assembly uses a barrel shaped spring to provide clearance for the spring within the lower well.

6 thoughts on “Rochester B Two Stage Power Valve

  1. I’m looking for a power valve for a rochester B carb. i need the “screw cap” that the spring and bearing sets in. do you know where i can find one. it looks exactly like the above image.

    thanks! george

  2. Dear Mike,
    I have a 1954 Chevy truck that has been in the family for years. I’m having it restored and nearly done. However in my hot rod days I always told people that I know enough about carbuators to leave them alone. I have had the original Rochester “B” rebuilt by a friend and found out when we started it, something was very wrong. Flooding over etc. I have the float set correctly but I’m going to rebuild it myself.
    My question is how is the power valve removed? I tried last night by turning but I don’t want to scar it. Does it screw out or is it pressed in. I’m soaking it with cleaner now. With Respect,ed P.S. the old guy has been a good friend of the family for many years and I’m sure looking forward to a stock original show piece.

Leave a Reply

Your email address will not be published. Required fields are marked *