48A30-04105 Injection Pump Assembly with PS8A-HL-25 Governor – For Mitsubishi S16R / S16R2 Marine & Generator Engines
For high‑output marine propulsion and prime/standby power generation, the Mitsubishi S16R and S16R2 engines are undisputed heavyweights. Their ability to deliver continuous, reliable power under extreme conditions depends entirely on a precisely calibrated fuel injection system. The 48A30-04105 Injection Pump Assembly – factory‑paired with the PS8A‑HL‑25 hydraulic governor – is the complete, ready‑to‑install solution engineered specifically for these 16‑cylinder workhorses.
Unlike a bare pump, this complete assembly includes the dedicated PS8A‑HL‑25 governor, pre‑set for isochronous (constant speed) operation – making it the ideal choice for generator sets where frequency stability is non‑negotiable. In this guide, we examine its robust construction, exact engine fitment, common failure signs, professional installation steps, and why Rsolid Engine Parts is the preferred global supplier for S16R fuel system components.
1. Structural Features & Advantages of the 48A30‑04105 Assembly
The 48A30‑04105 is a complete, factory‑matched fuel injection pump and governor assembly. Its design reflects Mitsubishi’s heavy‑duty engineering philosophy:
Complete plug‑and‑play assembly – Includes the pump housing, 16 precision‑lapped plunger & barrel sets, delivery valves, and the pre‑attached PS8A‑HL‑25 governor. No separate governor sourcing, linkage fabrication, or complex alignment required.
PS8A‑HL‑25 hydraulic governor – Specifically calibrated for generator and constant‑speed marine applications:
Isochronous control maintains precise 50/60 Hz frequency regardless of load changes.
Instant load acceptance with rapid torque‑rise response for large motor starts.
External droop & idle adjustments for fine‑tuning on‑site without disassembly.
Matched 11.0 mm plunger pairs – Lapped to sub‑micron tolerances, guaranteeing identical fuel delivery across all 16 cylinders. This eliminates uneven firing, reduces crankshaft torsional vibration, and extends bearing life.
Forged alloy steel camshaft – Induction‑hardened cam lobes withstand the high torque loads from the engine timing gear, maintaining precise injection advance even at 100% continuous load.
High‑strength cast iron housing – Engineered to absorb vibration and resist thermal distortion during prolonged high‑temperature operation (up to 120°C continuous).
Corrosion‑resistant internal coatings – Protect plungers and barrels from the acidic by‑products of marine fuels and moisture ingress.
Key operational benefits for marine and genset operators:
±0.5% frequency regulation – The PS8A‑HL‑25 ensures stable grid frequency for sensitive electronic equipment.
4‑6% fuel savings – Balanced cylinder metering and optimised timing reduce overall specific fuel consumption.
Cleaner combustion – Precise fuelling minimises black smoke during startup and load transients, helping meet IMO and local emission regulations.
True direct fit – Bolts directly to the engine timing case with factory‑specified mounting points – no modifications needed.
2. Compatible Engine Models & Typical Applications
The 48A30‑04105 assembly with the PS8A‑HL‑25 governor is factory‑calibrated for the following Mitsubishi S16R engine variants:
| Engine Model | Typical Applications |
|---|
| Mitsubishi S16R‑PTA | Prime power gensets (50Hz / 60Hz), offshore platform power, large trawlers |
| Mitsubishi S16R‑YPTA | Standby & continuous marine propulsion, ferry main engines |
| Mitsubishi S16R2 (high‑boost) | High‑speed crew vessels, dredgers, mining haul trucks, fire‑pump drives |
| Governor Unit | PS8A-HL-25 – hydraulic isochronous/droop governor (generator‑optimised) |
Critical cross‑reference: The 48A30‑04105 often supersedes earlier numbers such as 48A30‑04100, 48A30‑04102, and is commonly listed under Mitsubishi industrial parts catalogues. Always confirm your engine serial number (prefixes like 45001, 46001, or S16R specific codes) and the current pump flange type to ensure a perfect match.
3. Common Failure Modes & Professional Installation Guidance
Typical Warning Signs to Watch For
Frequency fluctuation / hunting under steady load – Often caused by contaminated hydraulic oil inside the PS8A‑HL‑25 governor or a sticking flyweight assembly.
Black smoke during load application – Over‑fuelling due to worn plungers or a misadjusted max‑fuel stop screw.
Hard starting or failure to start – Loss of residual injection pressure from leaking delivery valves or a stuck control rack.
Fuel dilution of engine oil – Indicates a failed camshaft oil seal or cracked pump housing – immediate shutdown is critical to avoid main bearing failure.
Uneven exhaust gas temperatures – Points to individual cylinder mis‑delivery, often from a scored or stuck plunger.
Step‑by‑Step Installation & Replacement Protocol
Absolute cleanliness – Flush the entire fuel supply line and install new primary & secondary filters. Even microscopic debris will score new plungers within minutes of operation.
Proper lubrication – Use clean diesel fuel or specified light assembly oil on plungers, rollers, and governor linkage pivot points. Never use grease – it attracts debris and can cause governor sticking.
Precise timing mark alignment – Align the punch marks on the pump drive gear with the engine's flywheel TDC. For S16R series, typical injection timing is 10–14° BTDC – refer to your engine data plate.
Staged torque application – Mounting flange nuts: 55 ± 5 N·m using a cross‑tightening sequence. Over‑torquing distorts the housing and binds the plungers.
Replace delivery valve holders & copper washers – Tighten to 60 ± 3 N·m. Always use fresh washers to guarantee a leak‑free high‑pressure seal.
Thorough system bleeding – Open the bleed screw on the pump body and prime until bubble‑free fuel flows. Then bleed each high‑pressure line to the injectors individually.
Governor post‑installation tuning – After starting, set the idle speed and maximum speed stop per the engine nameplate. If operating in parallel genset mode, adjust the droop screw to match the load‑sharing module (typically 0‑5% droop).
Performance validation – Perform a cylinder cut‑out test to confirm all 16 cylinders deliver within ±3% variation. Conduct a load‑acceptance test from 0‑100% – response must be smooth without overshoot or excessive black smoke.
4. Why Rsolid Engine Parts Is Your Trusted Global Supplier
Rsolid Engine Parts has been a trusted name in diesel fuel injection for over 15 years, serving marine fleets, power plants, and industrial workshops across six continents. Here’s why the 48A30‑04105 from Rsolid is the right choice:
OEM‑grade manufacturing – Produced in IATF 16949 & ISO 9001 certified facilities, using identical base materials, heat treatment, and surface finishes as genuine Mitsubishi pumps.
100% bench‑tested and calibrated – Every assembly is run on a Bosch‑licensed calibration stand. We provide a detailed test report – including individual cylinder delivery curves, governor droop characteristics, and speed‑response graphs – with every shipment.
Global stock and fast logistics – Strategically warehoused in Asia, Europe, and North America. Typical delivery 3‑7 working days to major seaports and international airports.
Competitive wholesale pricing – Attractive volume discounts for fleet operators, rebuild workshops, and distributors. Enquire about our core exchange / return programme.
Free expert technical support – Our in‑house engineers provide timing charts, governor tuning manuals, wiring diagrams (for electronic add‑ons), and remote diagnostics via WhatsApp or email.
Industry‑leading warranty – 18 months / 3,000 hours against material and workmanship defects – with a fast‑track, no‑hassle replacement process.
Contact Rsolid Engine Parts Now
📧 Email: amy@rinjector.com
📱 WhatsApp: +86 15975376778
Whether you need a single 48A30‑04105 assembly for a scheduled overhaul or a bulk order for a fleet of S16R2 vessels, Amy and her team will provide a detailed quotation, stock availability, and shipping schedule within 2 hours. We also supply complementary parts – plunger & barrel kits, gasket sets, delivery valves, and fuel filters – for complete fuel system rebuilds.
Choose the 48A30‑04105 complete injection pump assembly from Rsolid – engineered to deliver stable power, low emissions, and uncompromised reliability for your Mitsubishi S16R / S16R2 generator and marine engines.
