When your diesel outboard starts acting up, this 142-page Yanmar D27A, D36A service manual PDF breaks down the complete powerhead, drive unit, and electrical system to get your motor back on the water. Inside, you get complete electrical wiring diagrams, hydraulic schematics for the tilt cylinder, and step-by-step disassembly instructions for the lower gear case. Packed with exploded views and a dedicated section for pinion gear backlash adjustments, this guide takes the guesswork out of marine repairs. Verify the crankshaft side gap is within the 0.15-0.45 mm standard before you lock down the injector tap set bolts to 2.6~2.8 kgf-m. Stop relying on vague forum advice for a marine diesel. Download this bookmarked file, load it on your tablet, and take the factory answers straight to the dock.
What's Inside This Yanmar D27A, D36A Manual
| System | Pages | Key Topics |
|---|---|---|
| Chapter 1 General | 4-16 | Specifications, Exterior View, Cross-Sectional View |
| Chapter 2 Disassembly and Reassembly | 17-59 | Preparations Before Disassembly and Reassembly, Tools, Measuring Instruments and Service Equipment, Exploded View of Parts, Reassembly Procedures |
| Chapter 3 Inspection and Service Procedures for Engine Parts | 60-89 | Service Procedures for Engine Parts, Cylinder Block, Piston and Connecting Rod, Crankshaft, Camshaft, Cylinder Head, Valve Arm Case, Intake/Exhaust Valve Arm and Unit Injector |
| Chapter 4 Reassembling and Servicing of Drive Unit | 90-110 | Swivel/Steering Bracket, Clamp Bracket, Upper Case, Bottom Cowling and Fitting Parts, Lower Gear Case, Cooling Water Pump and Cooling Water Piping, Steering Handle |
| Chapter 5 Piping Diagram | 111-113 | Fuel System Components, Lube Oil System Components, Cooling Water System Components, Thermostat Valve Opening Temperature |
| Chapter 6 Electric Equipment | 114-124 | Generator, Starting Motor, Warning Device, Wiring Diagram |
| Chapter 7 Service Standard | 125-131 | Service Standard Table |
| Chapter 8 Main Bolt Tightening Torque | 132-134 | Engine Bolt Tightening Torque, Drive Unit Bolt Tightening Torque, General Bolt and Nut Tightening Torque |
| Chapter 9 Backlash Adjustment | 135-137 | Pinion Gear Backlash Adjustment, Forward Gear Backlash Adjustment, Reverse Gear Backlash Adjustment, Propeller Shaft Backlash Adjustment |
| Chapter 10 Periodical Inspection | 138-139 | Periodical Inspection Table |
| Chapter 11 Option | 140-142 | Diesel Outboard Propeller Guard Holes |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Injector tap set bolt tightening torque | 2.6~2.8 kgf-m | p. 133 |
| CW pump case tightening bolt torque | 0.7~0.9 kgf-m | p. 133 |
| Overheat alarm buzzer activation | O (activates) | p. 118 |
| Cylinder head temperature OFF | 115°C | p. 119 |
| Crankshaft Side Gap (Standard) | 0.15-0.45 mm | p. 125 |
| Flywheel Tightening Nut Torque | 16.5~17.5 kgf-m | p. 133 |
| Pinion Gear Tightening Nut Torque | 9.0~10.0 kgf-m | p. 133 |
| Backlash between Pinion and Forward Gear (Standard) | 0.1~0.25 mm | p. 129 |
Yanmar D27A, D36A Common Problems This Manual Covers
Yanmar D27A or D36A sensitivity to poor fuel quality with hard starting and immediate engine stalls p. 69
Inspect the unit injectors and verify the fuel valve opening pressure is exactly 200 ±5 kgf/cm² as detailed on page 69. Check the fuel pipe joint bolts and torque them to 1.5~2.5 kgf-m. Replace the fuel filter every 50 hours to prevent contamination.
Manual Section: Unit Injector Inspection & AdjustmentLoss of power under heavy load with continuous overheat alarm buzzer activation and high-temperature shutdown p. 115
Test the water temp thermostat valve to ensure it opens at 72°C. Inspect the cooling water pump on page 115 and verify the clearance in the impeller shaft direction measures 0~0.5mm. Replace the impeller if worn to restore proper cooling flow.
Manual Section: Warning Device DiagnosisHard starting after long storage periods with heavy engine vibration, thick exhaust smoke, and rough idle p. 79
Check the timing belt tension on page 79 and adjust it to exactly 15kg. Drain stale fuel from the system and bleed the lines. Clean the fuel filter housing and replace the element if it has exceeded the 50-hour replacement interval.
Manual Section: Engine Component Inspection & Service ProceduresLower gear case grinding noise and poor acceleration when shifting into the forward drive gear p. 129
Measure the backlash between the pinion and forward gear. Adjust the shims on page 129 until the clearance is within the standard 0.1~0.25 mm. Drain the lower unit and refill with exactly 0.55 L of drive unit lube oil as specified on page 6.
Manual Section: Backlash AdjustmentFrequently Asked Questions
What are the torque specs for Yanmar D27A/D36A head bolts?
The manual specifies the tightening torque for the cylinder support set bolt (M16 x 1.5) as 11.0 to 15.0 kgf-m. While not explicitly "head bolts," this is the closest related torque provided for the cylinder assembly in the main bolt tightening torque section.
What are the torque specs for Yanmar D27A/D36A injector or pump bolts?
The tightening torque for the injector tap set bolt (M8 x 1.25) is specified as 2.6 to 2.8 kgf-m. This torque is also referred to as the unit injector tightening torque in the reassembly procedures.
What is the engine oil capacity for the Yanmar D27A/D36A, and what type of oil is recommended?
The engine oil full amount is 2.4 liters, with an effective amount of 1.0 liter. The recommended engine oil type is API service grade CD class SAE 15W-40. For the lower unit, the capacity is 0.65 liters of 80W90 YANMAR's driving gear oil.
What are the recommended service intervals for fuel filter and lube oil filter for Yanmar D27A/D36A?
Both the fuel filter and the lube oil filter element should be checked, refueled, or replaced every 50 hours or once a month, whichever comes first.
How quickly can I access this manual after buying?
This is a 142-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.
Am I able to print pages from this manual?
Yes, print as many copies as you want, and there are no restrictions. Many mechanics print the section they need and bring it to the shop floor.
Does this Yanmar D27A, D36A manual include wiring diagrams?
Complete wiring diagrams are included, covering all electrical circuits, harness routing, and connector pinouts for the Yanmar D27A, D36A.
Document Quality
This is a scanned document, so you cannot search or copy text directly as it lacks an OCR layer. The text is generally crisp and readable, though some pages exhibit slight fading or minor blur. Diagrams and illustrations are raster images, which pixelate when zoomed, but their labels are mostly readable. Pages are largely clean with occasional minor scan artifacts, slight skewing, or faint background discoloration. There are no notable blank or filler pages in this document.
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