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MG MGB Technical - Water in fuel

I've just finished a respray and after putting everything back together (including the fuel tank which I'd removed and emptied for the respray) I had some trouble starting it.
I replaced all the plugs, checked the timing (it was out a bit) and went through all the usual checks to find out what was wrong.
Turned out it was the fuel pump not getting power. Fixed that and got the engine started but it ran very rough. Spent the last couple of days toying around with the timing trying to figure out what was wrong.
Finally thought I'd got it set right, it was idling fine and when I backed out the driveway it all seemed okay. Got just around the corner and started up a hill and it all died on me.
In desperation I called NRMA roadside assistance. He shows me the fuel filter and it was full of water. Damn.
I'm positive it didn't come from the tank I reinstalled. That was bone dry and I put a fresh 5 litres of premium directly in the top spout before asembling the hose to the filler cap. I can only assume it was somehow trapped in the lines and/or the pump.
Common sense tells me to just replace the filter and blow out the lines with my compressor. I guess I have to remove the lines from the pump to do this, but otherwise I'm not sure if there's anything else I can do.
How much damage (if any) am I likely to have caused the engine? What's the best way to be sure I've got totally clean fuel lines other than what I have planned?

Any help would be greatly appreciated.
D O'Brien

It could have been in the fuel. It will not hurt the engine, in fact a little water injection helps. I would try cleaning out the pump and lines then if you hit problems again you wil have to drain the tank. You will see the water as globules at the bottom of the tank as it is immiscible with petrol.
S Best

I was planning on using lots of petrol to flush the tank, but then a friend told me he vaguely remembers when he was younger they used kerosene to flush water from fuel tanks. Then somebody else said "No, you use methylated spirits not kero."
Now I'm confused. Should I stick with my original plan to use petrol, or is there some merit in these kero and metho ideas.
D O'Brien

Hi.

If a fuel tank or container is not full the remaining space will be full of air, and that air contains water vapour.
If the container gets cold, the water vapour will tend to condense out, and fall towards the lower part of the tank / container. If there is fuel in the tank the relatively light fuel will float on top of the condensed water, so the water cannot evaporate away again and tends to accumulate at the bottom of the tank. Maybe something like this happened to you ?.

If there isn't a lot of water in there (and I can't see why there should be) a bottle of fuel dryer (which you simply put in the fuel tank) might solve your problem.

I understand that it allows the water to mix uniformly and harmlessly with the fuel, and it simply passes through the engine with the fuel as you drive.

I suspect that some quality fuels include a little fuel dryer in the additive package, does anyone have more info ?.

Don
Don

This thread was discussed on 31/08/2005

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