Log XLVI - What can you find in the fuel tanks

In my previous post, I mentioned about the loss of engine power i.e. low RPM, and suspected that it might be the bacterial in the diesel that was causing the problem. The Volvo Penta mechanic was very professional and kind to advise me a cheap and effective way to find out the cause.

The test method is to simply use an alternative source of diesel instead of from the fuel tanks. If the engines can operate normally with the alternative fuel source, then we can be very sure that the fuel is the culprit.

Here was how the preparation went. Firstly we had to get a small fuel tank and some clean diesel from the petrol station. I thought this was an easy task, so I just picked up any plastic bottle I could find in the marina and drove off to a petrol kiosk. When I squeezed the pump trigger for the diesel to flow, nothing happened. Then I found out that the pumps at our petrol kiosks will not work if we are not pumping directly into our cars. The petrol kiosk attendant told me that I had to purchase a metal tin to buy diesel in order for it to work. By the way, Esso does not sell metal tins but Shell does.

I was quite confused. What is the difference between pumping into a plastic bottle instead of a metal tin? Anyway I just followed the attendant's instructions. This time when I squeezed the trigger of the pump, diesel started to flow out into the metal tin! Somehow there is some kind of mechanism in the pump that can differentiate the material of the container. It can only start pumping fuel when it detects metal.

After getting my alternate fuel source, we went back to set up the new fuel system on the boat.

The tin can full of diesel was secured tightly using two elastic bands. A fuel hose was inserted into the top opening and sealed with tape to prevent spillage. After setting up the new fuel source, we went out for a sea trial. The engine's performance was great! In fact it was much stronger. We were able to pick up speed faster and could achieve a higher top speed. The clean diesel really made hell lots of difference, together with the new turbo charger.

Now we had concluded that the problem lied with the dirty diesel, the next step was to make it clean. We thought of several solutions of how to clean the fuel tanks. Drill a small hole at the bottom of the fuel tank to let the diesel drained out - but this is too dangerous, the drilling might trigger an explosion. Cut a hole at the side of the fuel tank big enough for hands to go through to clean the interior - but this operation is too time consuming and costly. Eventually we decided to pump the dirty diesel out from the small fuel sender hole on top of the fuel tank and see how clean the diesel we could make achieve.

We inserted a hand pump through the fuel sender opening and push the inlet pipe all the way to the base of the tank, so that we could reach any debris or water which would be at the bottom. This was what we pumped out.

Unbelievably dirty. From far it even looked like mud. And if you take a closer look.

You can only see a thin layer of polluted diesel floating on top. The bottom dark layer was actually water mixed with the bacteria sludge. I was surprised that the engine could even work at all with this kind of mixture!

So we kept pumping until we could see the golden colour diesel.

As we had to properly dispose the dirty diesel to a designated area in the marina which is about 500 meters away, we had to use small 20 liters containers to store the diesel for easier handling. After every four full containers, we had to carry them to the disposal point to empty them and repeat the process again. We made three trips altogether which is equivalent to twelve containers which works out to be more than 200 liters of diesel!

We were unable to achieve the pure full transparent golden colour diesel but it looked much better. After that we changed all the external fuel filters and all the engine and generator filters. It sounds tedious? Yes, it was.

We did a sea trial the following day. With only two passenger load, almost empty fuel tanks and most importantly clean diesel, Artemis 1 was flying during the sea trial. And so it closes the chapter of the case of the dirty diesel... for now.

Log XLV - Bacteria in the Diesel?

It has been a very long time since my previous post. That is because I can finally keep myself busy, not with repairing the boat but to enjoy the boat... at last. However the boat can never be perfect and once a while Artemis 1 will catch a cough or cold, which when given some treatment, she will be healthy again.

Artemis 1 was feeling very lethargic a few days before the virus strike and finally on one fine day, the engine just slowed down. It did not stall but it just simply could not go fast. There are hundreds of reasons to cause an engine to slow down, but the first thing that came to my mind was the turbo charger. Base on the RPM where it hovered around 2,400 and could not go up, I suppose that the turbo might not be working and hence the engine could not receive sufficient power.

And so, I started to dismantle the turbo charger to look at the turbine fans. This was what I saw.

One of the fins was chipped off and a few others had crooked edges. It took me about 4 hours to take the whole turbo charger out from the engine. When I brought it to the turbo servicing shop, the mechanic upon further dismantling the turbo, found that actually many of the parts were worn off and leaking engine oil. The repair would costs as much as a new turbo. And so, I ordered a new turbo from them and installed it back myself.

This was the turbo charger taken out and put inside a NTUC plastic bag for transportation to the turbo service shop.

The installation process of course took longer than the dismantling. And when it was finally done, I took Artemis 1 out for a sea trial. Even before I could go one nautical mile from the marina, the engine slowed down again. That was a new $1,800 turbo and it did not solve the problem. So I decided to consult someone with more experience this time, and also to shorten my down time of using the boat.

No more approaching independent mechanics from unknown sources, I decided to call the official Volvo Penta service agents to diagnose my engine. There were many rumours of how expensive the agent will charge, which was the main reason that keep putting me off from calling them. This time I decided to try it myself to experience it personally.

So the agents came in a team of two. First difference, independent mechanic is usually solo, they will only bring an assistant along when there is a major operation. Volvo Penta sent two mechanics down just for diagnostic. I had roughly brief them on my engine conditions before the appointment was fixed, it definitely would not constitute to a major operation, but Volvo Penta assigned two person to come down to get the job done faster.

Second difference, independent mechanics often dive straight into the part that they thought might be causing the problem - just like I dived straight to replacing the turbo charger. The official agent follows a standard protocol of checking all the basic operations of the engine before diagnosing the problem. This will strike off the possibility that the engine fault is not caused by external factors. And this was exactly what happened in my case.

Some independent mechanics which I consulted on the phone told me that the problem might be the fuel pump, the fuel injector or the turbo charger. The agent however, said that there can be too many possibilities, so they started to check right from the fuel source down the fuel pipe lines, to the filters, to the pumps, to the injectors, etc. in a very systematic manner.

It did not take long for them to discover the problem. The agent found out that the fuel filters were full of slimy stuff which was caused by water infiltration into the diesel, which provided a suitable environment for bacteria to grow, and flourish in this case. The slimy stuff was actually bacteria.

They were kind enough to advise me on what are the steps that I needed to do next. First, I have to establish that the fault is really caused by the bacteria. Second, if that is the case, I will have to flush out all the bacteria from the fuel tanks. If not, they would come back to diagnose the engine for me again. They explained to me step by step on how to test the engine on whether the bacteria was the culprit and how to flush the tanks if it was.

They could of course do all these for me but that would burn a hole in my pocket. Needless to say, as usual, it was time to get my hands dirty again. In my next post, I would show you how we tested the engine and what we found in the fuel tanks!