Diesel fuel problems part 2

Continuing what BIO fuel can do for us boaters - first I want to explain what has been happening in recent years.

The authorities want to reduce pollution and in an effort to achieve this have reduced the amount of sulphur in the fuel. Also to make world fuel stocks go further a proportion of BIO fuel has been added to Diesel.

The BIO part is renewable as it comes from various crops which can be grown. When prepared to be added to the diesel it is known as FAME (Fatty acid methyl esters). In general use the diesel supplied for road use is likely to have 5% but can have up to 20% of this FAME added.

It has been recognised that this can be harmful to engines and is considerably more difficult to store than normally refined diesel.

This is a shortened list of the problems that boaters are likely to find by using low sulphur FAME - and some solutions I have found:-

1/ Diesel injection systems, especially older versions, rely on sulphur for lubrication. Therefore increased wear can be caused by low sulphur fuel. Many people are adding 2 stroke oil to their fuel to overcome this. We now add 2 stroke oil at the generally recommended ratio of 1 to 200 and when not added we notice that the engine does not run so smooth. ( I have read a paper from a German university who found that of all the additives available for diesel fuel, 2 stroke oil is by far the best)

2/ FAME causes some rubbers such as fuel lines and ‘O’ rings soften, swell or harden and crack. This was the problem with our injector pump, a pair of small ‘O’ rings had swollen and jammed a tiny valve. We now carry several spare ‘O’ rings. It has been seen to melt the fuel pipes on some older engines.

3/ Free methanol in FAME corrodes aluminium, Zink and some other parts sometimes found in injection systems.

4/ It can cause increased blocking of injector nozzles.

5/ Water dissolved on the fuel can cause a reversion of the fatty acid which will block filters.

6/ There will be an increase in the DIESEL BUG as FAME supports the various types of bug much better than normal diesel.

7/ There tends to be more sediments which will cause filters to block quicker.

8/ The FAME tends to break down any crud which has formed inside the fuel tank and hoses / pipes etc. This causes quicker filter blocking.

9/ There can be a high volume of particles which can sediment and block filters. Solid impurities can also increase wear.

10/ It can have a high viscosity at low temperatures which can cause overheating especially in distributor type injector pumps. This was also one of our problems.

11/ There are problems with storing this type of fuel. Even commercial suppliers are recommended not to store it for longer than 6 months due to it going off and the BUG growing. This sort of makes a mockery of using it in a boat where it is likely to be unused over the winter.

The actual list is considerably longer than this short version but this shows what a disaster it can be for a boat engine, especially the older engines of which there are many.

As a surveyor I try to keep abreast of the latest safety developments and about 5 years ago I replaced all the fuel lines on Ti Gitu with the latest EC – RCD approved fuel lines. I now find that there can be problems with some of these and if you are replacing yours it may be worth asking the manufacturer if they are suitable for FAME fuel. (Just in case you take some aboard without knowing)

I do not know what is happening about this problem in the Mediterranean and Caribbean where I do know most suppliers are adding FAME to the road fuel, however it has been recognised as a major problem in the UK and now many marinas have approached their suppliers and are receiving FAME FREE FUEL.

I would like feedback from anyone with information in other countries. Just post a comment or email me please.

I have spoken to marina managers who have said that they have difficulty with some suppliers who seem to know nothing about FAME FREE FUEL. One marina manager actually found that despite being assured by his fuel rep that he was being supplied with the correct fuel later found that the company knew nothing about it and were supplying normal road fuel.

The engine manufacturers are worried about FAME to the point that several are saying that for most of their engines, if it is found that fuel with more than 5% FAME is found to have been used then any guarantee / warranty is void. BEWARE.

So in summary, I suggest that all boat owners with slightly older engines (roughly more than four or five years old) make absolutely sure not to take on any FAME fuel and even those with the very latest engines which should be OK with FAME do not store the fuel for long. Also it may be a good idea to carry a good supply of fuel filters.

Happy sailing.