Home › Engines › Yamaha ME421STI (Hydra Drive)

Yamaha ME421STI (Hydra Drive) Marine

Name: Yamaha ME421STI (Hydra Drive) marine engine
Brand: Yamaha Inboard
SKU: YA-ME421STI

Yamaha Inboard Yamaha ME421STI (Hydra Drive) · YA-ME family: specifications, its industrial/tractor base engine, cross-referenced parts and where to buy them.

🚜 Base engine likely

The Yamaha ME421STI is a marinized Toyota 1HD-series 4.2 L inline-6 diesel (1HDT lineage). Many internal service parts cross to Toyota Land Cruiser 1HD channels — but Yamaha used proprietary pistons/rings under high boost and some marinizing-specific parts, so verify fitment before swapping. source

240 hp176.5 kW

4164 ccdisplacement

94×100 mmbore × stroke

6-cylcylinders

from 2000year range (approx)

Turbo + ICaspiration

240 hp 6-cyl; RIBnet / classifieds consensus; turbo-intercooled STI badge

📋 Full specifications 2 🚜 Industrial / tractor base 🔧 Aftermarket 5

Cheaper-part coverage · 1/8

🚜 Base engine ✓🌀 Impeller💧 Raw-water pump🛢️ Oil filter⛽ Fuel filter🌡️ Thermostat➰ Belt⚓ Anode

A ✓ means at least one cheaper channel — aftermarket, the tractor/industrial base engine, or a standard component — exists for this engine in that category.

Parts by section · 53 assemblies

The exploded parts diagrams for the Yamaha ME421STI (Hydra Drive), grouped by system. Open a figure for its callout part numbers and per-variant quantities.

Other

Fig 1 — CYLINDER HEAD Fig 2 — CYLINDER BLOCK Fig 3 — TIMING GEAR COVER. REAR END PLATE Fig 4 — CRANKSHAFT. PISTON Fig 5 — CAMSHAFT. VALVE Fig 6 — OIL PUMP Fig 7 — OIL FILTER. COOLER Fig 8 — WATER PUMP (CIRCULATION)Fig 9 — GLOW PLUG, INJECTION NOZZLE Fig 10 — NOZZLE HOLDER ASSY Fig 11 — ADJUSTING SHIM (FOR NOZZLE HOLDER ASSY)Fig 12 — INJECTION PUMP Fig 13 — FLYWHEEL HOUSING 1 (ME421STIP1/STIP2)Fig 14 — FLYWHEEL HOUSING 2 (ME421DTIP1/DTIP2)Fig 15 — MOUNTING 1 (ME421STIP1/STIP2)Fig 16 — MOUNTING 2 (ME421DTIP1/DTIP2)Fig 17 — OIL COOLER 1 Fig 18 — OIL COOLER 2 (ME421DTIP1/DTIP2)Fig 19 — LUBRICATION SYSTEM Fig 20 — VENTILATION Fig 21 — WATER COOLER (HEAT EXCHANGER)Fig 22 — WATER COOLING 1 (OUTLET)Fig 23 — WATER COOLING 2 (THERMO UNIT)Fig 24 — SEA WATER PUMP 1 (ME421STIP1/STIP2)Fig 25 — SEA WATER PUMP 2 (ME421DTIP1/DTIP2)Fig 26 — SEA WATER PUMP SUB-ASSY Fig 27 — WATER FILTER (SEA WATER)Fig 28 — POWER STEERING PUMP Fig 29 — INTAKE MANIFOLD Fig 30 — FUEL FILTER Fig 31 — AIR CLEANER Fig 32 — AIR COOLER Fig 33 — EXHAUST 1 Fig 34 — EXHAUST 2 (TURBO SUPERCHARGER:ME421STIP1/STIP2)Fig 35 — EXHAUST 3 (TURBO SUPERCHARGER:ME421DTIP1/DTIP2)Fig 36 — TURBO SUPERCHARGER ASSY Fig 37 — THROTTLE CONTROL ATTACHMENT Fig 38 — SHIFT ASSIST UNIT (ME421STIP1/STIP2)Fig 39 — SHIFT CONTROL (ME421DTIP1/DTIP2)Fig 40 — RESERVE TANK. TOOL Fig 41 — GENERATOR Fig 42 — STARTING MOTOR Fig 43 — ELECTRICAL 1 Fig 44 — ELECTRICAL 2 Fig 45 — ELECTRICAL 3 Fig 46 — PULLEYS. BELTS Fig 47 — LABELS. CAUTIONS Fig 48 — TRANSMISSION 1 (HOUSING:ME421DTIP1/DTIP2)Fig 49 — TRANSMISSION 2 (ROTATION & REDUCTION:ME421DTIP1/DTIP2)Fig 50 — OPTIONAL PARTS 1 Fig 51 — OPTIONAL PARTS 2 Fig 52 — OPTIONAL PARTS 3 Fig 53 — OPTIONAL PARTS 4

📚 Manuals & Sources

Specs— none yet

Operator's Manual— none yet

Service / Workshop Manual— none yet

Parts Catalog / List— none yet

More📖 Boat Inboard Engine Manuals Boat Manuals

External links — we host none of these documents.

Yamaha ME421STI (Hydra Drive) — Affiliate Parts Search

Amazon eBay AliExpress

As an Amazon Associate I earn from qualifying purchases. Other links (eBay, AliExpress) are also affiliate links — they help pay for the site, at no extra cost to you. More

Category: Marine
Engine family: YA-ME
Year range (approx): from 2000
Cylinders: 6
Rated output: 240 hp (176.5 kW)
Bore × stroke: 94 × 100 mm
Displacement: 4164 cc
Max rpm: 3800
Aspiration: Turbocharged + intercooled

Related YA-ME engines

Yamaha ME200S (Hydra Drive)Yamaha ME200STI (Hydra Drive)Yamaha ME370STI (Hydra Drive)Yamaha ME380T Yamaha ME400 Yamaha ME400L Yamaha ME420DTI (Hydra Drive TRP)Yamaha ME420STI (Hydra Drive)Yamaha ME421DTI (Hydra Drive TRP)Yamaha ME421ST (Hydra Drive)Yamaha ME422HO (Hydra Drive high output)Yamaha ME422STI (Hydra Drive)Yamaha ME432STI (Hydra Drive)