Quick Fuel Technology 34-9 Secondary Metering Block with idle mixture screws User Manual


Installation Instructions

34-9 Secondary Metering Block with idle mixture screws

Congratulations on purchasing a Quick Fuel Technology® billet secondary metering block equipped with idle mixture screws for carburetors with four corner idle system.

Installation is essentially the same procedure as replacing a conventional metering block. There are a couple of features and tuning aspects of this metering block you should become familiar with. At the top of the straight “V” is the idle feed restriction. This screw-in restriction controls the fuel side of the idle and off-idle air/fuel mixture. Your metering block comes with .033” idle feed restrictions. The number 33 will be stamped on the head of these restrictions.

The emulsion holes, the three threaded holes in each of the serpentine slots do not have any restrictions intentionally. The emulsion holes are pre-calibrated and drilled in to the bottom of the well. These pre-calibrated emulsion holes are adequate for the majority of applications.

In the future should you wish to make the emulsion feature adjustable it is possible to do so by drilling the bottom of all six wells to approximately .050” or 3/64”. Remove the main jets and power valve before drilling. Be careful to only drill deep enough to break into the main well.

After you have successfully drilled all six holes (three per side), use a quality carburetor cleaner, spray in to the top angle channel (booster discharge port) to dislodge any metal shavings from the drilling process, then use compressed air blow out the main well again from the top (booster discharge port) down. The recommended starting point is with all three emulsion holes being


CAUTION: Do not make drastic emulsion size changes as you can significantly alter the air/fuel ratio and could cause engine damage. It is highly recommended that when experimenting with emulsion calibration you consult one of the many books available on carburetor modification and use one or more devices that monitors air/fuel ratio throughout the operating RPM range.

Service and calibration parts can be ordered through your performance parts distributor or directly from Quick Fuel Technology®, 129 Dishman Lane, Bowling Green, KY 42101,1-270- 793-0900. Thank you for purchasing this performance product from Quick Fuel Technology®.

P/N 99-2

© Quick Fuel Technology ® 2004