Part of the Yanmar Repair Manuals.
Crack the fuel filter loose on a Yanmar 4LHA and you have bought yourself an airlocked injection line; the bleeding procedure in this operation manual is the difference between a few minutes of hand priming and an afternoon of fruitless cranking.
It is Yanmar's factory operation manual, publication 49961-205431, for the 4LHA-HTP, 4LHA-HTZP, 4LHA-DTP, 4LHA-DTZP, 4LHA-STP and 4LHA-STZP marine diesels. The English section covers engine specifications, control panel and alarm functions, daily and cold-weather starting, clutch operation for the marine drive, long-term storage, and the full periodic inspection schedule from the initial 50 hour service through the 2000 hour items.
The numbers you actually reach for are here too: 15W40 lube oil and 13.0 liter capacity, 750 rpm low idle, V-belt deflection, a standard bolt torque table, and a troubleshooting chart for when an alarm sounds. 705 pages as a PDF download, bought once and yours to keep.
What's Inside This Yanmar 4LHA Series Manual
| System | Pages | Key Topics |
|---|---|---|
| For Safe Operation | 4-8 | Warning Symbols, Safety Precautions, Location of Product Safety Labels |
| Explanation of Product | 9-22 | Engine Specifications, Names of Parts, Major Servicing Parts, Control Panel, Remote Control Handle |
| Before Operation | 23-31 | Fuel Oil, Lube Oil & Cooling Water, Supplying Fuel, Bleeding the Fuel System, Supplying Marine Drive Oil, Supplying Cooling Water |
| How to Operate | 32-41 | Inspection Before Starting, Starting, Adjusting the Engine Speed, Clutch Operation for the Marine Drive, Stopping the Engine, Long-Term Storage |
| Maintenance & Inspection | 42-54 | List of Periodic Inspections, Periodic Inspection Items |
| Trouble and Troubleshooting | 55-56 | Troubleshooting |
| System Diagrams | 57-63 | Piping Diagram, Wiring Diagram |
| Spanish | 69-135 | - |
| Italian | 136-264 | French, German |
| Finnish | 265-388 | Dutch |
| Swedish | 389-512 | Norwegian |
| Danish | 513-574 | - |
| Greek | 575-636 | - |
| Portuguese | 637-698 | - |
| Appendix | 699-705 | - |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Engine Lube Oil SAE Viscosity | 15W40 | p. 15 |
| Engine Lube Oil Capacity (All) | 13.0 l | p. 15 |
| Lube Oil Filter Part Number | 127695-35150 | p. 47 |
| Lube Oil Filter Torque | hand tight + 3/4 turn with filter wrench | p. 47 |
| Bore x Stroke | 100x110 mm | p. 13 |
| Displacement | 3.455 L | p. 13 |
| High idling rpm | 3700 ± 25 rpm | p. 13 |
| Low idling rpm | 750 ± 25 rpm | p. 13 |
| Lube oil capacity (All) | 13.0 L | p. 13 |
| Cooling water capacity (Engine) | 15 L | p. 13 |
| Recommended battery capacity | 12V×120Ah | p. 13 |
| V-belt tension (give) | 8~10mm | p. 54 |
Yanmar 4LHA Series Common Problems This Manual Covers
Airlocked fuel system after filter change
Swap the fuel filter or run the tank low and the injection pump loses its prime, so the engine cranks clean without firing. The manual walks through bleeding the system step by step so you are not guessing at which fitting to open first.
Manual Section: Bleeding the Fuel System p. 26Overheat alarm while underway
A cooling alarm partway through a run often comes down to low cooling water. The manual covers checking and refilling the cooling water correctly, which matters on a closed-circuit marine diesel where a quick top-up done wrong just buys you the same alarm later.
Manual Section: Supplying Cooling Water p. 29Black smoke and sluggish acceleration
Heavy dark smoke with weak throttle response is one of the most reported 4LHA complaints, frequently traced to a starved air intake rather than the injection pump. The troubleshooting table pairs symptoms like this with their likely causes before you start pulling parts.
Manual Section: Trouble and Troubleshooting p. 55Slack V-belt and weak charging
A loose or glazed belt slowly drags down alternator output until one morning the batteries will not spin the starter. The periodic inspection items include belt checks, with the correct 8 to 10 mm of give specified so you are not tensioning by feel.
Manual Section: Periodic Inspection Items p. 44Engine will not catch on restart
Grinding away at the starter after a failed start is how good starters die young. The manual gives the correct restart procedure after a starting failure, so you fix the cause instead of cooking the cranking circuit.
Manual Section: Restarting After Starting Failure p. 35Stuck and corroded after long layup
An engine parked for a season without preparation comes back with gummed fuel, surface rust and seized accessories. The manual lists the layup steps before storage and the checks to run before asking it to work again.
Manual Section: Long-Term Storage p. 40Frequently Asked Questions
Which Yanmar engines does this manual cover?
The 4LHA series marine diesels: 4LHA-HTP, 4LHA-HTZP, 4LHA-DTP, 4LHA-DTZP, 4LHA-STP and 4LHA-STZP. It is Yanmar publication 49961-205431, and the same content applies across all six variants.
Is this a full workshop manual with rebuild clearances?
No. It is the operation manual: starting, running, clutch operation, periodic maintenance and troubleshooting. The Engine Specifications section gives base data such as 100 x 110 mm bore and stroke and 3.455 L displacement, and there is a standard bolt torque table, but not overhaul clearances like bearing fits or ring end gap. p. 10
What lube oil does the 4LHA take, and how much?
15W40, with a total capacity of 13.0 litres (page 15). The Lube Oil section covers grade and handling, and the periodic inspection schedule sets the oil and filter change intervals. p. 24
How do I bleed air out of the fuel system?
The Bleeding the Fuel System section gives the full procedure for purging air after a filter change or a run-dry, so the injection pump picks up prime again without endless cranking. p. 26
Is this Yanmar 4LHA-HTP & variants Operation Manual a digital download?
A 705-page Operation Manual in searchable PDF format, available the moment you complete checkout. View on computer, tablet, or phone, with no shipping wait.
Am I able to print pages from this manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
Does this Yanmar 4LHA-HTP & variants Operation Manual have electrical diagrams?
Yes. You'll find an electrical wiring diagram covering the main wiring layout.
Reviews
There are no reviews yet.