Need the factory specs to fix your job site lighting rig? All 275 pages of this Yanmar LB446H service manual pdf focus on one thing: getting your LB446HB and LB446H Floodlight Projector back to factory condition. Open up to complete electrical wiring diagrams showing exact circuit paths for the generator and lighting arrays. You get step-by-step disassembly procedures for the diesel engine, a full troubleshooting section covering low compression and starter failures, and detailed exploded views to guide your entire rebuild. Lock down the M16 lighting unit assembly nut to 49-66 lbw-ft, then verify the projector is pushing exactly 130 V before sending it out. Working in the dark costs you money. Grab this bookmarked download, pull it up on your shop tablet, and find the right values instantly.
What's Inside This Yanmar LB446HB, LB446H, LB446HB/H Manual
| System | Pages | Key Topics |
|---|---|---|
| Floodlight Projector | 2-81 | Cover, Foreword, Contents, Backcover |
| Generator | 82-146 | Cover, Introduction, Contents, For Safe Operation (Warning Symbols, Safety Precautions, Location of Warning Labels) |
| Cover | 147-148 | Introduction |
| Service Information | 149-151 | General Safety, Serial Number Location, Service Rules |
| Specifications | 152-158 | Cross Sectional Views |
| Service Standard | 159-168 | Intake/exhaust Valve Seats, Valve Spring, Piston, Connecting Rod, Crankshaft and Main Bearing, Oil Pump (Trochoid Pump) |
| Disassembly and Reassembly | 169-187 | Tools, Meters and Instruments, Tightening Torque, Maintenace Schedule, Disassembly Procedures |
| Checking and Servicing | 188-245 | Cylinder Head, Piston and Piston Pin, Connecting Rod, Crankshaft, Flywheel and Main Bearing |
| Toroubleshooting | 246-261 | No Fuel Injection Sound, Low Compression Pressure, Failure of Starter Motor, Insufficiently Charged Battery, Unexpected Reverse Rotation at Startup, Abnormal Exhaust Color |
| Test Run | 262-264 | Before Starting, Starting, Operation, Stopping |
| Helical Inserting Part for Repair | 265-267 | Size of Helical Inserting Part, Drilling, Tapping, Insertion, Where Helical Insert Part CAN Not Be Used |
| Appendix 1 Difference Between Parts Under Spec. S and D | 268-270 | Crank Case Cover, Camshaft Assy, Flywheel, Piston, Cooling Fan Case, Starting Motor |
| Appendix 2 Detail of Special Tools | 271-273 | Oil Seal Fitting Tool, Valve Stem Seal Fitting Tool, Flywheel Tightening Handle, Flywheel Extractor |
| Colophon | 274 | First Edition, All Rights Reserved, Engineering & Development Dept., Construction Equipment Division, Products Support Group, Yanmar Technical Service Co., Ltd. |
| Spine Title | 275 | Yanmar, Service Manual, Model, LB446HB/H |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| LB446H | ||
| Lighting unit assembly nut (M16) tightening torque | 49 to 66 lbw-ft (67 to 90 N-m) | p. 33 |
| All Models | ||
| Lamp replacement part number | 1-3010010-10 | p. 48 |
| Floodlight Projector Rated Voltage | 130 V | p. 14 |
| Floodlight Projector Current | 3.3 x 4 A | p. 14 |
| Floodlight Projector Lamp Rated Life | 20000 h | p. 14 |
| Generator Rated Output | 1.7 kVA | p. 98 |
| Generator Fuel Tank Capacity | 15 L | p. 98 |
| Generator Lube Oil Capacity (Upper Limit) | 0.8 L | p. 98 |
| Intake/Exhaust Valve Head Clearance | 0.15±0.05 mm | p. 126 |
| Fuel Injection Pressure | 19.6 MPa | p. 127 |
| Floodlight Projector Mast Group Bolt Torque (M10X25) | 24 to 33 N-m | p. 38 |
| LB446HB | ||
| Coupler button screw (M10X35) tightening torque (for balloon type) | 24 to 33 lbw-ft (33 to 45 N-m) | p. 31 |
Yanmar LB446HB, LB446H, LB446HB/H Common Problems This Manual Covers
Yanmar LB446H floodlight does not power on or works intermittently under load
Inspect the lighting unit assembly connections and wiring harness for loose terminals. Verify the generator outputs the rated 130 V. If securing the lighting unit assembly nut, torque it to 49 to 66 lbw-ft (67 to 90 N-m) as specified on page 33.
Manual Section: Generator Floodlight Projector IssuesOne or more lamps fail to illuminate while the generator engine runs smoothly
Check the wiring diagram on page 67 to trace the voltage drop to the faulty ballast. Verify the bulb has not exceeded the 20000 h rated life. Replace dead bulbs with part number 1-3010010-10, as listed on page 48, and inspect the socket for corrosion.
Manual Section: Floodlight Projector Lamp & Mast IssuesGenerator starter motor not rotating or fails to start engine in cold weather
Test the battery voltage and inspect the starter relay terminals for corrosion. Adjust the intake and exhaust valve head clearance to 0.15±0.05 mm following the specifications on page 126. If the engine cranks but refuses to fire, verify the fuel injection pressure reaches 19.6 MPa.
Manual Section: Generator Engine No-StartBalloon type projector coupler button loosens and mast vibrates excessively during operation
Inspect the mast assembly for missing fasteners and check the outrigger deployment. Torque the M10X35 coupler button screw to 24 to 33 lbw-ft (33 to 45 N-m) as detailed on page 31. Verify the M10X25 mast group bolts are secured to 33 to 45 N-m (24 to 33 lbw-ft).
Manual Section: Floodlight Projector Lamp & Mast IssuesFrequently Asked Questions
How to reset the error code on YANMAR LB446HB light tower?
The manual does not describe specific error codes or a procedure to reset them for the YANMAR LB446HB light tower. Troubleshooting is based on symptoms and provides corrective actions for various malfunctions, such as lamps not lighting or mast issues, rather than error codes.
What are the torque specs for the cylinder head bolts on YANMAR LB446H generator?
For the YANMAR LB446H generator, the cylinder head nuts (M8x1.25) should be tightened to a torque of 20.2 - 23.1 lbw-ft (27.4 - 31.4 N-m). It is recommended to apply oil to the face of the threaded part and use a hexagonal dimension 12 tool for tightening.
How to reset the maintenance timer on YANMAR LB446HB?
The manual does not provide a procedure for resetting a maintenance timer on the YANMAR LB446HB. The Hour meter (item 3 on the control panel) digitizes the integrated service hour of the generator and is used as a standard for periodic checks, but there is no mention of a reset function for it.
What are the common error codes for YANMAR LB446H diesel engine?
The manual does not list specific error codes for the YANMAR LB446H diesel engine. Instead, it provides troubleshooting charts based on symptoms such as the engine not starting, engine stopping, or abnormal engine speed, along with their possible causes and remedies.
Is this Service Manual a digital download?
This is a 275-page searchable PDF ready for immediate download. Works on any device, so pull it up on your phone while you're under the hood. No shipping, no waiting.
Are there any print restrictions on this Yanmar LB446HB, LB446H?
Absolutely. No DRM or copy protection. Print the whole manual or just the pages you need. Any home or office printer works.
Does this manual have electrical diagrams?
Yes, this Yanmar LB446HB, LB446H Service Manual includes complete electrical wiring diagrams, wire routing, and connector pinouts.
Document Quality
This document is a scanned PDF with an OCR layer, allowing you to search and copy the main text content, which is crisp and easy to read throughout. Diagrams and illustrations are raster images, meaning they may pixelate at high zoom, but their labels are generally readable. The pages are clean with no noticeable scan artifacts, stains, or skewed content. There are a few blank "MEMO" pages interspersed within the document.
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