Fuel Treatment

Its worth doing to know what is there and act accordingly. It would not be good to switch to your last reserve tank on a long passage and find you had a problem.

Give me a call if you want to discuss.
 
the boat is on the hard and stored for winter so won't be able to swirl it around to mix it.

Add sufficient fuel treatment (forthe 6 litres in your tank) to a gallon of diesel in a fuel can and add that to tank on the boat. It will mix with the tank contents. You can give it a generous dose of treatment if you wish.
The seems to be an assumption that the fuel will have diesel bug, which is not proven in your case. I think there is an increased risk of bug since the fuel became low sulphur and since some bio diesel might be present. But I do know people who use their boats very little and they have not had and diesel bug issues. So the presence of bug remains a risk , not a certainty.
I think you can get a diesel bug test kit which might be worth considering althogh the cost might not be worth the trouble.
It's best to leave the diesel tank full over the winter but probably too late for that if your boat is ashore.
 
For commercial boats that have a high throughput of diesel say a tank full or more a week , its like a car you don't need it.

For a leisure boat that is lightly used and spends the winter idle the cost of a good diesel biocide as a preventative measure is much better and lower cost than trying to remove a dose of the bug or cleaning and repairing fuel pumps and injectors one its got through to the engines.

Also wherever possible remove water from your tanks on a regular basis don't rely on the diesel prefilter alone, that way the bug will be reduced even further as it needs water.
 
I agree with Bandit. Always try to remove the habitat for diesel bug which is of course water. Diesel can be stored for long periods without problems, just as long as there is no water ingress. Once there is water there will almost always be bug shortly after.
 
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