Engine trouble: the background

For anyone who’s followed this journey for even a little while, they’ve probably already heard many references to our engine failure. I wanted to write about it in some detail, but it’s a long story so I’ve broken it into parts. This post is more about the details of our main engine problems, and so is a bit more technical, but hopefully not as tedious to read as it has been to experience it…

The story starts before we knew the engine was going to die. There was a period of relative calm in the Southern Ocean between New Zealand and Rapa, when we were running the engine to charge the batteries and make slightly better progress. We noticed the exhaust had some black smoke; since the wind was slight and from behind us, the smell wafted over the boat, too. I thought the turbo might be dying, since it has been sitting, rusting externally, for a few years. But the turbo turned out not to be the biggest problem.

When the next time came to charge the batteries, after several more days of sailing (about 2 weeks after leaving New Zealand), we tried to start the engine, but it wouldn’t start. I checked the glow plugs to confirm they were still working. It didn’t seem like there were any other obvious pre-start problems, so we cranked again, and eventually got a loud, fast-paced coughing whine as it ran out of control for about a half-second, then stopped.

Hmm, this was bad… Really bad. And obviously a fuel problem; and more importantly, the whining gasp indicated that there was a problem with the injector pump’s speed governor. Until this, I’d been able to fix almost anything that had stopped working on the boat, but I was pretty sure this would not be easily repaired.

I opened the main fuel filter’s water separation drain and out comes salt water! So there is salt water in the fuel tank. That could have come from the fill point on deck, if the cap was not tightened properly; or maybe from the vent line, which allows air in and out of the tank as fuel is removed or added. I checked the second fuel filter’s separator drain – more salt water. Definitely bad!

Since water is heavier than diesel, it collects at the bottom of a fuel tank and is quickly drawn out toward the running engine.  To prevent water reaching the engine, boat fuel filters have water separators (essentially, a vortex generator that assures the water is re-separated before going through the filter element and collected in the bottom of the filter case).  As long as the water is drained out of the bottom of these filters, none will enter the engine. In the past, I’ve been careful about taking on good fuel (some places have water in their fuel) and check the separators regularly; but in all these years, I’ve only drained a few milliliters from each filter – most likely from condensation in the tank.

I suspect that the black, smelly smoke was from running the engine for its last time, on a mixture of water and diesel. I’ve seen engines with dead turbochargers putting out lots of black smoke, so I jumped to that conclusion. I don’t know much about running an engine on a mixture of water and fuel, but I now suspect it might cause a similar symptom.

This time, it wasn’t milliliters of water I removed, but liters! When I finally siphoned only diesel from the tank, I pumped the water out of the lines and filter cases, cleaned the cases, and replaced the filter elements. I had never done anything with my engine’s injector pump before – it just worked. For 1400 engine hours, I never had to touch it or even understand how it worked. So I didn’t know about the bleed screw at the injector valve end of the pump until a few days later, when reading through my mostly useless engine “owner manual” (for example, it tells me to take the engine in for service when it’s time to change the coolant).

The term “bleeding the fuel system” usually refers to loosening a fitting somewhere in the fuel system and manually operating the engine’s fuel pump until all the air has bubbled out and only fuel dribbles out. But it’s useful for removing water, too. Bleed points I did know about were at the two filters and at the inlet to the pump. But bleeding at this other point, the outlet of the injector pump, would not have made any difference. The pump was ruined and so were the injectors (one in each cylinder).

Repairing this injector pump is not an easy task. It took me weeks to assemble (and fabricate!) the right tools just to remove it from the engine! Fortunately, I had access to Rapa’s community workshop (many thanks to everyone who helped, especially Alex!) or I would not have been able to do anything. Apparently, nowhere and nobody in French Polynesia will work on my engine’s pump – it has to go to France, Germany or the US.

Even the process of identifying the necessary parts could fill a whole blog post! During the three weeks on Rapa when I worked mostly on the pump, I spent a lot of time studying as many documents and blog posts as I could find on the Internet about rebuilding injector pumps and injectors. All at a blazing speed of 40kb/s!

I ordered the parts via email from Eugene, Oregon, which were expedited from Germany, on-shipped to Vancouver (paid the import duty to cross the border; thanks a lot Canada!); the next day, it joins Sara on a 20 hour flight through Los Angeles and Tahiti to Raivavae in the Australs of French Polynesia.

On reassembly, I notice that there are pump parts that are not moving properly – they have a light coating of rust! Since disassembly in Rapa, they were cleaned, coated with diesel and wrapped in clean cloth, but they should have been soaking in a diesel bath. I clean these rusty parts again, make sure they move properly and reassemble the pump.  Back at the boat, I find another stuck part, so we’re back at the workshop the following morning.  What a way to spend time on a beautiful, remote island in the South Pacific!

Eventually, I reinstalled the pump but connected the injector piping in a funny way, so that the injectors are not inside the engine, but rotated and hovering above the engine. This allows me to crank the engine and watch to see if the injectors are spraying diesel correctly (Raivavae did not have a “pop tester”, but Rapa did, so I checked the injectors there with a spare, known-good nozzle). This told me that the pump was providing the high pressure and the injector nozzles were working correctly.  Dusk was settling in, so I decided to wait until the next day to actually start the engine.

I’ve written about that fateful day in “Engine Drama”….

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