Holley 4160 Vacuum Secondary Adjustment

Back to tuning the vacuum secondary system.

Holley 4160 vacuum secondary adjustment. Convert that 4160 to a 4150 so you bought a newer 0 3310 vacuum secondary 750 holley for a great price but later you realize it is the 4160 style with the secondary metering plate. If we could make our vacuum operated secondary carburetors perform better by opening the secondaries mechanically it would be in our advantage to do so since all that vacuum actuating hardware is expensive and requires much time and money to calibrate. Use these simple tips to adjust the idle mixture screws on holley carburetors to eliminate hesitation rough idle backfire stalling and more. The most noticeable difference in the 4160 is the thin secondary metering plate which is used in place of the secondary metering block.

In this session we decided to tackle how to adjust and tune secondary opening rate for a vacuum operated holley. Holley 4160 overview holley 4160 adjustable float carburetor image summit racing the holley 4160 carburetor was introduced as an updated version of the 4150 in the 1970s. Holley offers some tips on how to properly operate and adjust four barrel carburetors with vacuum secondary throttle blades. Improperly set idle mixture screws are often the reason for carburetor symptoms such as hesitation rough idle backfire stalling hard starting engine surge and.

Holley carburetors have idle mixture screws that control the air fuel ratio at idle. The video describes the various rate secondary springs how to change them and the testing procedures to follow to make sure the secondaries open properly for best performance.