Engine
- 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.
- 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)
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.
- 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 + ...
This fucking thing is a nightmare to get to, if ever there was one.
This should have been easy.
But no such luck. The impeller is behind the alternator, wedged between the water pump and the starter.
I tried pulling out the old impeller with needle nose pliers, channel locks, vice grips.. no dice. Not enough leverage, not enough space 😿 . Luckily, Tony gave me an impeller puller he's never had fit anything (fit mine like a glove). The space is too tight for the handle, but with that unscrewed I was able to get the arms in behind the impeller and then pry it out.
(Tools make the impossible possible)
(replace the outer seal too)
To put the new one in, add some water-based lube (KY or similar works) and zip-tie the fins down; wedge it in there and slide it through the zip tie so it pops out just as it's in the housing, and we're done ✅.
| Date | Action | Parts | Next Due |
|---|---|---|---|
| 2026-05-02 | Replace impeller | Johnson 4JH2E kit | 2027-05 |