Friday, September 30, 2005

Fuel pump


I've not said too much about the engine, or any engine room operations for quite some time. This has mainly been because I've got so much else going on and the engine is in pretty good shape, relative to the rest of Lady Jane, so is low priority.

Fuel pumpThe engine does need to be started, and run, from time to time though. I try to do this about once a month, though I suspect with winter coming on I'll run it more often as it's a great heater.

For a while now, I've known of a small diesel leak in the return pipes from the injectors. I finally got to have a look at this a little more carefully.

To explain the problem means explaining a little about how the fuel system works:

The diesel is stored in one of four tanks in the engine room. These tanks are only for storage, and do not feed either the main or the donkey engine directly.

To get fuel to the engines, diesel is pumped up to what is known as a 'day tank', this sits above both the main and donkey engines. Diesel is than gravity fed, through filters, to each of the engines as required.

Any unused diesel fed to the main engine is circulated to a smallish diesel return tank, below the engine room deck plates, from there it is pumped back up to the day tank by means of a continually running fuel pump. This is the normal mode of operation for the pump when the engine is running.

To pump more diesel into the day tank when it gets towards empty, one of the four fuel tank valves needs to be opened, depending on which tank is to be used, and the diesel is either manually pumped into the tank, or is pumped using the diesel return pump by setting a valve to the correct position. Once the day tank is full, the fuel tank valve is closed and the retun pump valve is set back to the normal running position.

You can see the diesel return pump just to the left of the picture.

The problem I have is that the diesel return tank is full, hence the leaking pipe. What I don't know at this stage is if the pipe from the tank to the pump is blocked, or if the pump itself is broken.

I'll need to run up the main engine again, with the valves set to pump diesel from the main tanks, to work out what the problem is.

Either way, as you can see, it's going to be a dirty job to sort it out.

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