Holley Marine Supercharger Carburetor 850 CFM

Description: This is a Holley 0-80443 850 CFM Marine Carburetor expertly modified and designed for large cubic inch marine engines where a mechanical secondary 4150 model 4BBL is required. The supercharger modifications were done by a leading supercharger shop with over 40 years of proven design experience in supercharger applications. This carburetor is intended for use with draw-thru superchargers, and has a unique capability that allows its power valve to reference the intake manifold vacuum below the supercharger. This allows the power valve to operate as it should, based off intake manifold vacuum. A power valve provides further enrichment to the main metering system under load (low vacuum) conditions. Without this external referencing, the power valve would be "reading" the supercharger vacuum, which has no bearing on the engine load. During throttle up loading to get a boat on plane, there may be a significant vacuum under the carburetor due to the supercharger sucking in air, but in the intake manifold you may have low vacuum or slight boost, a condition that would signal a power valve to open and add fuel. Boost referencing will show the carburetor what the engine really needs from the power valve, based on load.Modified by Blower Drive Services (BDS) for use with draw-thru superchargersBoost referenced power valve for proper enrichment under accelerationFeatures a port in the main body for indexing the power valve to boost for draw through supercharging; Weiand B&M 174/177/250, Blower Shop, and most popular draw-thru blowersMilled choke tower for balanced air flowNovel U-Style vent tube, directs fuel/fumes back into the carburetor for safe operation while on rough watersPower valve anti-backfire check valve kit provides power valve blow-out protectionSpecialized calibration for marine supercharged applications, all fuel circuits balanced & calibrated30cc primary and 50cc secondary accelerator pumps for additional fuel under initial accelerationDual feed fuel inlets for constant high volume fuel deliveryMechanical Secondaries for perfect off the line launchesGold Dichromate finish for corrosion resistance and classic Holley looksChrome finished aluminum fuel bowls with dual sight glass windows100% wet-flow tested by Holley technicians to assure it arrives ready to runAll Holley Marine Carburetors are designed to meet Coast Guard specifications. A marine carburetors fuel metering system is calibrated to compensate for unique engine loads found on boats. Specifications:Barrels: 4Booster: Down LegCarburetor Use: MarineCFM: 850Choke: ManualMaterial: AluminumFinish: Gold Dichromate body, Chrome fuel bowlsModel: 4150Secondaries: MechanicalThrottle Bore: 1.750 inchMain JetsPrimary: 84Secondary: 88Power ValvesPrimary: 4.5Secondary: 4.5Idle BleedPrimary: .070Secondary: .059High Speed BleedPrimary: .028Secondary: .026Pump Nozzle SizesPrimary: 31Secondary: 31Carb Installation Instructions: 1. Set float levels (idling) to bottom of sight plug. No more than 6-7 lbs of boost pressure (8 lbs HO racing engines).2. Set idle mixture screws (engine warm) to max RPM or vacuum. Recommendations:Total Ignition Timing: 28-30 degreesMinimum octane fuel: 91 ** This is an open-box item, that is new and has never been used **

Price: 449 USD

Location: Tualatin, Oregon

End Time: 2024-11-22T21:02:16.000Z

Shipping Cost: N/A USD