How dirty is dirty?

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mick

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I've just drawn off a litre of diesel from the bottom of my tank. In it there are a few fairly large dirt particles and several others, small but clearly visible. This dirt represents a tiny percentage of the overall volume but I'm not sure how normal this is, hence the question. I change my Racor and fine engine filters every season.
 
You obviously have a gut feeling that it's time to look into cleaning the tanks so I'd follow it.

If there's dirt there in the bottom, you'll bounce around in a chop sometime and stir it up and your clean filter can clog up fast.

Happened to me and I'm meticulous about fuel and oil filters, and of course if it's going to affect you it's sods law it'll happen at the worst time. I had to change my fuel filters many miles out in the Atlantic with the boat rolling all over't shop. Much better to do it in the marina I can assure you.

You know this is what you want to hear! Happy cleaning! /forums/images/graemlins/smile.gif
 
If the litre came from the very bottom, I'd expect it to have some dirt in it. A few solid particles, a bit of water, some black gunge. When you find a significant amount, like half of your litre, it's definitely time to clean out. Work on the basis that everything in there might get to the filter. Would it block?
I just use a pela to 'hoover' the bottom of the tank.
Does your engine draw from the very bottom of the tank?
What state was your filter in last time you changed it? If its more than about 20% full of black stuff, your tank needs a clean imho!
You could go to a lot of trouble to remove 50cc of water, only to get more in when you fill up.
I'm assuming you have the normal two filter setup? CAV and engine?
It's a judgement and we don't know your setup, or how you use your boat, so can't take responsibility for your motor stopping, or for you spending unnecessary hours polishing your fuel tank! It would be easy to say clean it, but I've got by for 7 years just removing any water I can get out with the pela and changing the primary filter every year. I don't do a lot of engine hours, but I've never had a fuel problem, apart from a bit of a scare when some air worked through the lines after a filter change.
HTH?
 
For the last four years I have used the same 25 litre plastic container to store diesel for cruise's during the year.

Its been filled from marina pumps in this country and Brittany.

This year I noticed just how much muck is in the bottom of this container. The muck clogged the funnel filter that I was using to pour the last few litres of diesel nto the tank.

Goodness only knows how much filth is in the bottom of the tank, which I have never cleaned out.

Be interested to know how this muck can be removed without to much mess on the decks.
 
A pela type vacuum oil extractor is good for this, but its worth fitting a wider bore hose to it, and possibly a valve, as the standard tube can clog. The tap (1/4 turn ball type) enables you to pump up some vacuum, then manoeuvre the tube around the bottom of the tank, rather than trying to pump with one hand and steer it with the other! Diesel will flow quicker than the oil it was intended for. Use a weighted hose into the tank, via the filler, just keep hoovering until only clean diesel appears. Pour off into 25litre can to settle, after a day or two recover most of the diesel from the can. Definitely worth doing from time to time. Dispose of crud with waste sump oil.
Do you think the increase in crud is due to biofuel in the diesel? I wonder if road fuel is not intended to be stored as long as old fashioned gas oil?
 
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