Installation Instructions for 16500 Nitrous Switch

Note: Designed for 4150 style carburetors. This includes Holley® HP series, Proform™ and Quick Fuel Technology Q& P Series carburetors. Bracket will work with standard and aftermarket adjustable secondary arms.

1. We recommend removing the carburetor from the engine prior to beginning this step (if so installed) to eliminate any debris from entering the engine. A carburetor fixture or a vise with soft or protected jaws works best. For the past few years, Holley® has been tapping these holes with a #8-32 thread. If your carburetor is threaded simply install the bracket and tighten the screws. If not you will have to tap the holes prior to installation. Use a tap lubrication fluid to lubricate the threads. To avoid loading the tap with material, the tap should be backed off about a half a turn for each complete thread formed. Upon completion the tap is backed out of the hole and all chips are blown clear.

2. Install the carburetor on the engine.

3. Install the bracket and switch as pictured in illustration 1 and tighten the screws.

4. Test the switch for activation by moving the throttle to wide open. You should hear a click from the switch indicating activation. An alternate test method would be to use a voltage/ohm meter.

5. Adjust the switch as necessary by loosening the two bolt and nut assemblies and rotating the switch on the bracket until engaged and re-tighten. Be sure to also check the carburetor secondary bracket for alignment. No binding of any sort should be present.

6. Wiring is achieved by a normally open method along with the common for ground (see illustration 2).