ZEXEL RHD6-PC Hydraulic Governor | ZEXEL RHD6 & RHD10 Governor | P/N 105856-0422 | Mechanical Hydraulic Governor for Marine Diesel Engines

Manufacturer

ZEXEL Corporation (Formerly Diesel Kiki Co., Ltd.)

Country of Origin

Japan

Product Type

Mechanical Hydraulic Governor

Marine Application

Marine Main Engines, Auxiliary Diesel Engines, Marine Generator Engines, Industrial Diesel Engines

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Product Introduction

The ZEXEL RHD6-PC Hydraulic Governor (P/N 105856-0422) is a precision mechanical-hydraulic speed governor designed to provide accurate engine speed regulation for marine and industrial diesel engines. As part of the renowned ZEXEL RHD Series, the RHD6-PC combines proven hydraulic control technology with robust mechanical construction to ensure stable engine performance under varying load conditions.

The governor automatically regulates fuel delivery by responding to engine speed changes through a centrifugal flyweight mechanism and an internal hydraulic oil system. This provides smooth acceleration, reliable load acceptance, and excellent speed stability for continuous marine operation.

The RHD6-PC shares many design principles with the RHD6 and RHD10 governor families, making it a trusted solution for commercial vessels, fishing boats, offshore support vessels, marine generator sets, and industrial power plants.

SM MARINE SERVICE™ supplies New, Used, Exchange, and Professionally Reconditioned ZEXEL RHD6-PC, RHD6, and RHD10 Governors, including repair, calibration, overhaul, spare parts, and worldwide shipping.

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What is the ZEXEL RHD6-PC Governor?

The RHD6-PC is a self-contained hydraulic governor that automatically maintains engine RPM by adjusting the fuel injection pump according to engine load.

The governor is mechanically driven from the engine gear train. As engine speed changes, centrifugal flyweights move the pilot valve, directing hydraulic oil pressure to the servo piston. The servo piston then adjusts the fuel rack to restore the preset engine speed.

This hydraulic feedback system ensures excellent engine stability without requiring electronic control systems.

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Main Features

• Genuine Japanese ZEXEL governor
• Mechanical-hydraulic speed regulation
• Stable engine RPM control
• Built-in hydraulic oil pump
• Adjustable speed droop
• Compensating adjustment mechanism
• Heavy-duty aluminum housing
• Long operational life
• Reliable marine performance
• Easy overhaul and maintenance

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Main Components

The ZEXEL RHD6-PC typically includes:

• Governor Housing
• Hydraulic Oil Pump
• Flyweight Assembly
• Hydraulic Servo Piston
• Governor Drive Shaft
• Speed Adjustment Mechanism
• Droop Adjustment Assembly
• Compensating Needle Valve
• Governor Springs
• Bearings
• Oil Reservoir
• Output Shaft
• Seal & Gasket Kit
• Mechanical Linkage

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Working Principle

The governor continuously senses engine speed using a centrifugal flyweight assembly. When engine load changes, the flyweights move in response to RPM variation and control the hydraulic pilot valve.

Hydraulic pressure is directed to the servo piston, which moves the fuel control mechanism. The governor continuously balances fuel delivery with engine load, maintaining stable speed and minimizing hunting.

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Marine Applications

The ZEXEL RHD6-PC is commonly installed on:

• Main Propulsion Diesel Engines
• Auxiliary Diesel Engines
• Marine Generator Sets
• Fishing Vessels
• Tug Boats
• Cargo Ships
• Bulk Carriers
• Offshore Support Vessels
• Harbor Craft
• Industrial Diesel Engines

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Common Problems & Troubleshooting

Engine Hunting

Possible causes:

• Incorrect compensating adjustment
• Worn governor springs
• Air in governor oil

Oil Leakage

Possible causes:

• Damaged oil seals
• Worn gaskets
• Loose hydraulic fittings

Slow Governor Response

Possible causes:

• Contaminated governor oil
• Blocked oil passages
• Servo piston wear

Unstable Engine Speed

Possible causes:

• Flyweight wear
• Incorrect droop adjustment
• Bearing wear

No Governor Action

Possible causes:

• Broken drive coupling
• Hydraulic pump failure
• Internal governor damage

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Maintenance Recommendations

For maximum service life:

• Use the recommended SAE 20W-40 governor oil.
• Replace oil according to the service schedule.
• Inspect oil leaks regularly.
• Check linkage movement.
• Verify speed droop adjustment.
• Inspect seals and bearings during overhaul.
• Perform governor calibration after maintenance.
• Follow ZEXEL service recommendations.

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Why Ships Continue Using the ZEXEL RHD Series

Marine operators continue to rely on the RHD6-PC, RHD6, and RHD10 because they provide:

• Proven Japanese engineering
• Accurate speed regulation
• Excellent reliability
• Simple hydraulic operation
• Long service life
• Easy overhaul
• Worldwide spare parts availability
• Low maintenance costs

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Frequently Asked Questions (FAQ)

Is the ZEXEL RHD6-PC repairable?

Yes. Most units can be completely overhauled with replacement of bearings, seals, springs, hydraulic components, and recalibration.

Is this governor compatible with other RHD series models?

Many service procedures and spare parts are similar across the RHD6, RHD6-PC, and RHD10 series, but compatibility should always be verified using the part number and engine application.

Do you provide exchange service?

Yes. SM MARINE SERVICE™ offers exchange, repair, overhaul, and calibration services for ZEXEL hydraulic governors.

Do you supply new and reconditioned governors?

Yes. We supply New, Used, Exchange, and Professionally Reconditioned ZEXEL RHD6-PC, RHD6, and RHD10 Governors, fully tested before shipment.

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Short Product Description

The ZEXEL RHD6-PC Hydraulic Governor (P/N 105856-0422) is a precision mechanical-hydraulic speed governor for marine diesel engines and generator sets. It provides accurate engine speed regulation, dependable hydraulic control, and long-term durability, making it one of the most trusted governor systems used in commercial marine applications.

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User Manual & Technical Resources

Typical documentation includes:

• User Manual
• Operation Manual
• Service Manual
• Workshop Manual
• Parts Catalogue
• Calibration Procedure
• Maintenance Manual
• Installation Manual
• Troubleshooting Guide

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SM MARINE SERVICE™

SM MARINE SERVICE™ supplies New, Used, Exchange, and Professionally Reconditioned marine governors, engine automation equipment, and genuine spare parts.

We provide:

• Worldwide Supply
• Governor Exchange Service
• Governor Repair & Overhaul
• Calibration Services
• Genuine Spare Parts
• Technical Support
• Equipment Sourcing
• Fast Worldwide Shipping

Bangladesh Office
Samir Market, DT Road, Pahartali, Beside CDA Market, Chattogram, Bangladesh

China Warehouse & Support Center
Shanghai, China

Website
www.smmarineservice.com

Email
info@smmarineservice.com

WhatsApp
+8801818929292

Marketing Contact
Nazmul Hasan Bhuiyan

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