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Ethan Knox edited this page Apr 26, 2026 · 19 revisions

Engine

Specs

  • Yanmar 4JH2E, 50 hp inboard, freshwater-cooled diesel
  • Repowered 1998 (current engine)
  • Serpentine belt conversion driving the Balmar 120A alternator
  • Spare parts aboard: filters, belts, seals, wiring, etc.

Oil

  • Capacity (with filter): 4.8 L (5.1 qt)
  • Grade: Chevron Delo 400 XLE 15W-40 CK-4 (or any 15W-40 CD or higher)

Raw water pump — separately lubricated (gotcha)

The 4JH2E has two oil fill plugs, both labeled "oil" and physically interchangeable. Don't conflate them:

  • Valve cover = main crankcase (the 4.8 L fill above)
  • Pump assembly fill = raw water pump gear oil (~100–200 mL). Use vacuum extraction to drain — no drain plug.

The pump fill is a real maintenance item, not optional.

Fuel

  • 2 × 45 gal tanks (90 gal total)
  • Tanks were pulled, cleaned, and POR-15 protected in 2019
  • Fuel sender: resistive 2-wire, monitored via ESP32 + ADS1115 + voltage divider feeding HA. Standard Wema replacement is 240–33Ω (European) if current sender stops responding.

Service log

Date Service Notes
2026-04 Oil top-off, ATF top-off partial — full drain pending
2026-04 Earth ground bus contacts secured along run with zip-tied screw mounts (cable management; not an electrical change)

Maintenance schedule

  • Hours-based schedule pending ❓
  • Serpentine belt — last replaced ❓ (fix on next service)
  • Impeller — last replaced ❓ (fix on next service)
  • Coolant — last changed ❓ (fix on next service)
  • Primary + secondary fuel filters — last changed ❓ (fix on next service)

Cooling

  • Raw water → Groco strainer → impeller → heat exchanger → exhaust
  • Coolant change pending

Transmission

  • Kanzaki / Carl Hurth KBW20, direct drive
  • Transmission serial: 9729 (per survey)
  • ATF topped off 2026-04
  • Zip tie replacement pending

Dipstick gotcha

  • Single groove on the dipstick = MAXIMUM oil level. Dipstick tip = minimum.
  • Do NOT screw the dipstick in to check level — rest it on top of the filler hole. Screwing it in produces a false low reading.

Air

  • Air intake (pending replacement from Chesapeake Cove)
  • Air filter / snorkel replacement pending

Open items

  • Proper oil change (full drain)
  • Change impeller
  • Change water pump oil
  • New coolant
  • Replace air filter / snorkel
  • Replace zip tie on transmission
  • Clean Groco filter

Defiant

Systems

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