ESIESSENTIAL SHIPYARD INDUSTRIESEngine Service · Yanmar 4JH-CR
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Engine Service Checklist — Yanmar 4JH-CR

A step-by-step yard service record for the Yanmar 4JH-CR series — 4JH45 / 4JH57 / 4JH80 / 4JH110. Factory intervals, genuine Yanmar part numbers and interchanges, the non-engine Racor, and wipe-down/cleaning built into each step. Record what you actually installed, flag anything for the desk, then send the completed record to the North or South desk.

4cylinders
Factoryintervals + PNs
→ deskemailed

🛥️Vessel & engine

Who and what you're servicing — the engine variant sets which parts and turbo steps apply.

🗂️Service performed this visit

Which factory interval(s) is this visit?

Mark Done for the interval(s) you performed. Each system section below carries the interval badge for the task, so work top-to-bottom and mark every step.

Initial 50 h (break-in)
First-service items: engine & gear oil + filters, valve clearance, belt tension, control cable, shaft alignment.
250 h / annual
Oil & filters, fuel filters, impeller check, belt tension, intake element, mixing elbow, battery, alarms.
500 h / 2 yr
Mixing elbow, seawater passages, intake element, marine-gear oil filter, hoses.
1000 h / 4 yr
Valve clearance, coolant change, turbo blower wash (80/110), tighten major fasteners, wiring connectors.
Coolant service
Replace coolant — annually, or every 2 yr with LLC.
Rubber hoses (2 yr)
Replace rubberized fuel & water hoses every 2 years.
Unscheduled / repair
Diagnostic or repair visit outside the interval schedule.

🧽Pre-service prep & cleaning

Clean first, photograph, contain — so the service is provable and any new leak is visible.

Photograph engine & bay before starting
Before-photos for the record and to prove pre-existing condition.
Wipe down / degrease engine before service
A clean engine shows new leaks. Degrease and wipe so any post-service weep is obvious.
Record pre-existing leaks / issues
Note anything already weeping (oil, fuel, coolant, exhaust) before you disturb it.
Protect the ingress/egress path — decks, steps, sole
Lay canvas / drop cloths from the boarding point to the engine room. Protect gelcoat, teak, upholstery and cabin sole from foot traffic, tools and oil — no deck dirt, no staining.
Cover surrounding surfaces & hatch edges at the work area
Protective covering over adjacent joinery, berths and hatch edges so nothing gets marked while you work.
Lay out absorbent / contain fluids
Pads under filters and drains; nothing to the bilge.
Check / clean engine bilge
Clean bay = you'll see a new drip. Kaizen: leave it better than you found it.
Stage the cart — filters, oil, impeller, belt, gaskets
Right parts on the first trip = no return. Confirm PNs against the Parts section below.

⛽Fuel system — incl. Racor

The boat-side Racor and the engine fine filter — record the element PNs and micron used.

Non-engine — primary filtration (Racor)

50 hDrain the Racor / primary water separator bowl
Extra caution on common-rail engines — clean fuel is everything to the HP pump & injectors.
250 hReplace Racor primary element — record micron 121857-55710 (Yanmar primary)
Note the element PN and micron (typ. 10µ / 30µ). Non-engine, boat-side filter.
Check primary filter vacuum gauge / restriction
Rising vacuum = clogging element or a lift-side restriction.

Engine fuel system

250 hReplace fine (engine) fuel filter element 129A00-55800
Yanmar fine FO cartridge — CR engines demand clean fuel.
50 hDrain water & sediment from tank
Prime & bleed the fuel system
Prime, bleed air, confirm no leaks under running pressure.
Check fuel lines, connections & anti-siphon
Chafe, weeping unions, secure clamps.
2 yrReplace rubberized fuel hoses
Yanmar: replace fuel & water rubber hoses every 2 years.

🛢️Lubrication

Engine and marine-gear oil & filters — initial-50 then interval. Record grade and quantity.

DailyCheck engine lube-oil level (before & after)
Pull engine-oil sample for analysis
Draw from the warm used oil with a FRESH pickup tube (one per engine — no cross-contamination). Send out and log the sample number & lab.
50 h / 250 hReplace engine lube oil
Initial 50 h, then every 250 h / annual. Record grade & quantity in Parts below.
50 h / 250 hReplace engine oil filter 129150-35160
DailyCheck marine-gear oil level
50 h / 250 hReplace marine-gear oil
Initial 50 h then per gear maker.
50 hReplace marine-gear oil filter (if equipped)
Wipe filter seats / re-check for weeps after run
Clean the sealing face, run, confirm dry.

❄️Cooling system

Impeller, coolant, passages, heat exchanger & anodes — the overheat prevention pass.

DailyCheck seawater outlet flow during operation
DailyCheck coolant level
250 hCheck / replace seawater pump impeller 129670-42531
Inspect vanes, set, shaft; replace on any doubt.
Annual / 2 yrReplace coolant / LLC
Annually, or every 2 yr with Long Life Coolant. Confirm colour to Yanmar spec.
500 hClean & check the seawater passages
500 h / 1000 hInspect heat exchanger & end-caps / anodes
Yanmar coolers assemble dry — watch end-cap corrosion; renew zincs.
2 yrReplace rubberized water hoses

🌀Air intake & exhaust

Intake element, the mixing elbow (with factory PNs), and turbo wash on the 80/110.

250 hClean the intake silencer (air cleaner) element
250 h / 500 hClean or replace the exhaust / water mixing elbow
U- or L-type factory option. 45/57 use D29670-13200 / D29271-13270; 80/110 use D29677-13200 / D29677-13250.
1000 hWash the turbocharger blower — 4JH80/110 only
Turbo variants only. Check shaft play / noise while there.
Check crankcase breather diaphragm — 4JH45/57 only
Spring-backed diaphragm in the valve cover on the 45/57.
Inspect wet-exhaust hose, riser & clamps
Hardening, soot tracks, all-316 clamps.

🔗Belts & tensioner

V-ribbed / serpentine (multigroove) — tension to Yanmar spec; initial 50 h then 250 h; replace at 1000 h.

50 h / 250 hAdjust alternator V-ribbed belt tension
Initial 50 h then 250 h. Tension to Yanmar spec.
1000 hReplace serpentine (multigroove) belt
JH-CR specific belt. 80/110: 129677-42280 · 45/57: 129675-42280.
Check tensioner / idler bearing & pulleys
Spin for noise/roughness; glazing, cracks, black dust.

🔩Valves & fasteners

Valve clearance 0.20 mm cold (initial-50 then 1000 h), valve-cover gasket, and factory torque check.

Valve clearance (cold): intake 0.20 mm · exhaust 0.20 mm (0.008 in). Set on a COLD engine, each cylinder at TDC on compression. Same 0.20 mm across the 4JH45 / 57 / 80 / 110 — confirm against the current Yanmar operation manual for the build. Fit a new valve-cover gasket whenever the cover is removed — never reuse it.
50 h / 1000 hAdjust intake / exhaust valve clearance — 0.20 mm cold
Initial 50 h, then every 1000 h / 4 yr. Both intake & exhaust 0.20 mm (0.008 in), cold, each cylinder at TDC compression.
Replace valve-cover gasket
Required whenever the valve cover is removed — new gasket every time, don’t reuse.
1000 hTighten all major nuts & bolts
Torque-check fuel temperature sensor
Fuel temp sensor 129A00-51200 — 26–30 Nm.

⚡Electrical

Alarms, battery, connectors and charging — with the factory relay/fuse part numbers.

250 hCheck the alarm & indicators
250 hCheck battery electrolyte level
1000 hCheck wiring connectors
Corrosion, security, dielectric grease on the exposed ones.
Check charging output & grounds
Alternator output at the battery; clean grounds.
Relays / fuses reference — Starter relay 129927-77920 · Main relay 127677-77330 · Alt fuse 200A 127677-77060 · Starter fuse 50A 119578-77080.

🧬Common-rail service notes

What's field-serviceable vs Bosch-only on the CR fuel system.

Common-rail (Bosch CRS2-16) — service boundaries. Injectors and the HP supply pump are repaired only through a Bosch Service Shop; inner parts are not supplied to the field for safety. The common rail is not repairable — only the rail assembly is supplied. Keep the fuel scrupulously clean.
Injectors — condition / codes (no field disassembly)
Read codes; injector service is Bosch-only.
HP supply pump — leaks / codes
Field service limited; Bosch for internals. Fuel temp sensor torque 26–30 Nm.
Engine ECU & connectors — water / corrosion
ECU (w/o software) 1R1797-00101. Check connectors for water ingress.
Common-rail parts — HP pump 129A00-51000 · Rail 129C00-57000 · Injector 80/110 129677-53100 · Injector 45/57 129675-53100 · ECU 1R1797-00101.

⚙️Driveline

Shaft alignment (initial-50), coupling, shaft seal and controls.

50 hAdjust propeller shaft alignment
Initial 50 h and after any mount work.
Check coupling & set screws
Check shaft seal / stuffing box (drip)
50 hCheck remote control & shift cable operation

📦Parts & interchange reference

Genuine Yanmar part numbers with interchanges — plus a place to record exactly what went in.

The serpentine belt and the injectors are designed specifically for the JH-CR engine. Other parts interchange with the listed models and are available through the Parts Dept. (except the Engine ECU). Filter maintenance intervals are the same as the JH4/5 engines.

PartYanmar PNInterchange / note
LO (engine oil) filter129150-35160TNV and JH4/5
Fine fuel (FO) filter — cartridge129A00-55800TNV-CR
Primary fuel (FO) filter — cartridge121857-557104LHA-HTP
Serpentine belt (multigroove) — 4JH80/110129677-42280JH-CR specific
Serpentine belt (multigroove) — 4JH45/57129675-42280JH-CR specific
Seawater pump impeller129670-42531JH4/5
Injector — 4JH80/110129677-53100JH-CR specific
Injector — 4JH45/57129675-53100JH-CR specific
High-pressure supply pump129A00-51000TNV-CR
Common rail129C00-57000TNV-CR
Engine ECU (without software)1R1797-00101—
Starter relay129927-77920TNV
Main relay127677-773308LV, 6CX530
Fuse — alternator (200A)127677-770606CX530
Fuse — starter (50A)119578-770806LY3
Mixing elbow L-type — 4JH45/57D29670-13200same as 4JH5E
Mixing elbow — 4JH45/57 (alt)D29271-13270same as 4JH5E
Mixing elbow L-type — 4JH80/110D29677-13200same as 4JH4-TE/HTE
Mixing elbow U-type — 4JH80/110D29677-13250same as 4JH4-TE/HTE
Oil pressure sensor (C35 / VC10 panel)D29677-91250—
Fuel temperature sensor129A00-51200torque 26–30 Nm

Record what you actually installed

✅Post-service, clean-up & trial

Run, leak-check, Simple Green wipe-down, room check, trial and log — the finish that prevents callbacks.

ESI standard — we leave every engine room cleaner than we found it. A simple Simple Green wipe-down of the engine and the bay is the finish on every job. It’s how the customer knows the work was done and how the next new leak shows.
Run engine — check for leaks at every disturbed joint
Warm it up; walk the whole engine under pressure.
Re-check fluid levels hot & top off
Simple Green wipe-down of the engine
Simple Green and a rag — leave the engine clean so the next drip shows. Every job.
Clean the engine room — leave it cleaner than found
Wipe surfaces, pick up rags/parts, dry the bilge. We leave every engine room cleaner than we found it.
Dispose of used oil, filters & coolant properly
No fluids to the yard or the water.
Dock / sea trial — temps, smoke, shift, alarms
Confirm the whole job before hand-off. Kaizen: the whole job, not the task.
Remove protective coverings; check decks & sole for marks
Pull the canvas / drop cloths and confirm no dirt, oil or staining on deck, teak, upholstery or the cabin sole.
Engine-room check before hand-off
Final walk: no tools left behind, hoses/clamps secure, seacocks correct, nothing loose, everything stowed.
Update service log & record hours
Log the service, hours, parts and next-due.

📝Completion summary

What was done, and anything the desk needs to action.

— steps marked

Live count of Done vs Follow-up. Any follow-up carries its note and reference tag into the report to the desk.

📨Send the service record

Pick the Yard, preview, then send — the full record emails to that desk.