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Diesel quality.


johnmck

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Due to personal circumstances, our cruising this year has been limited to a rather narrow geographical area. This has also meant that twice recently, we have topped up with fuel at the same location.

Now the engine and Webasto heater have performed perfectly, but our Lockgate Refleks stove has not. Even on the highest setting, it barely functioned and created a lot of soot. I cleaned it, with no change. So, having run down the tank and filled from a different source, tried it again. The performance was much better, then better still after a further top up from another high volume source.

My conclusion is therefore that I obtained fuel of a lower Cetane rating than normal, during our restricted cruising. Anyone else had this?

 

 

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Dunno how a Refleks works but suspect that cetane is probably not a factor, that mostly relates to compression ignition.

But yes, fuel quality does vary, or perhaps more likely most is much the same but you you can get a bad batch. Last year somebody sold us a lot of really bad stuff. Engine smoked loads and could not get anywhere near full revs. I used most of it (with lots of additives to overcome any possible lack of lubricity) and eventually paid to get the last bit sucked out and disposed off to start again with a fresh tank.

It came from a reputable supplier but I can only be 99% certain so won't mention names, and almost certainly due to the fuel wholesaler or delivery driver rather than the boatyard themselves.

.............Dave

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I find it a bit sad that a lot of canalside diesel sellers have very little understanding of what they are selling. I have asked a fair few if their fuel is FAME free and some of the answers are a bit surprising, but then I am a techy sort of person. There is also a belief in some quarters that diesel and heating oil are one and the same so I would not be completely surprised if a one or two suppliers are not selling heating oil, this doesn't really explain your problems though.

..............Dave

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7 hours ago, dmr said:

I find it a bit sad that a lot of canalside diesel sellers have very little understanding of what they are selling. I have asked a fair few if their fuel is FAME free and some of the answers are a bit surprising, but then I am a techy sort of person. There is also a belief in some quarters that diesel and heating oil are one and the same so I would not be completely surprised if a one or two suppliers are not selling heating oil, this doesn't really explain your problems though.

..............Dave

35 sec heating oil has lots of bio content these days. Farmers and building contractors who use de regulated fuel insist on FAME free product. Apart from the propensity of bio fuel to attract water, there is a lack of lubrication to injector pumps, and many seals in filters and pumps are attacked by the bio content.

With regard to the Refleks stove, vaporising burners have a hard enough time with diesel without being diluted with bio content, which does not vaporise, but burns dirty.

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It might be worth contacting Refleks for comment.  In the Refleks 2000 manual, it states, "All regulators are set by the factory for diesel oil with an oil viscosity of 4,0 at a temperature of 20 degrees centigrade."  If you were supplied more viscous fuel it would cause the drip rate to reduce and this might be part of the problem.  If the same fuel supplied the engine, it would be interesting to examine the engine's fuel filters - even if you have to hacksaw one in half.

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Does the Reflecks use the same fuel supply, or is it fed from a dedicated tank?

If it is fed from a dedicated tank  take a sample of the fuel  and check it is not cloudy,  discoloured or slimy. If it is it will need trading with anti diesel bug stuff and polishing or replacing. 

Also how long have you left the Reflecks between use? 

If left long enough,  the diesel can evaporate in the float chamber, gumming up the needle valve, which controls the fuel flowers team into the stove. 

When I bought my boat the Kabola Old Dutch stove had not been used for 7 years and the diesel in the float chamber had completely evaporated which had seized the needle valve shut. It took brake cleaner to remove it and much fiddling to get the high and low flame settings set up properly again. 

Koukouvagia produced an excellent post on servicing diesel drip stoves, here:

 

Edited by cuthound
To add the last sentance.
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Hi. The Refleks is fed from the main fuel tank. As said, prior to the fill up from the suspected source, all was well. A good clean blue flame. After, it smoked a lot, to the extent that the inspection pane became completely black. Having now topped up twice from different high volume sources, all appears well again. Back to a steady blue flame even on low setting.

I do suspect the fuel as being the source of the problem.

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Is there a filter before the Refleks? 

  The engine and Webasto both have positive displacement fuel pumps, so the flow rate is not affected by viscosity.  The Refleks uses a drip feed to is very dependant on viscosity.  Did you keep a sample of the dodgy diesel?  I can imagine that if the flow rate was critically low, the oil pan would empty as the fuel burnt and the remnants would get too hot and start to carbonise - hence the soot.   This could occur even if the fuel was of good quality.

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2 hours ago, Ex Brummie said:

35 sec heating oil has lots of bio content these days. Farmers and building contractors who use de regulated fuel insist on FAME free product. Apart from the propensity of bio fuel to attract water, there is a lack of lubrication to injector pumps, and many seals in filters and pumps are attacked by the bio content.

With regard to the Refleks stove, vaporising burners have a hard enough time with diesel without being diluted with bio content, which does not vaporise, but burns dirty.

Weve done this quite a bit on the forum.

You can still get FAME free diesel on the cut but most sellers don't know how to get in. Norbury and ABC both sell it, and Norbury are cheap so there is no price premium. I think the bio helps the lubricity and detergency, its the low sulphur that degrades the lubricity. The issues are sucking in water, degrading quite quickly, and I suspect the increased possibility of a bad batch, I think bio factories are less consistent than mother nature  :D. The seal thing appears to have been overplayed and only gets a small number of older engines.

.............Dave

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I have not yet had any diesel problems ever!! It may well be that as a continual daily user not a hobby boater that helps matters. I have not spent one penny on " additives " again ever nor ever seen the dreaded bug. My usual stance is to fill up when needed, I don't ring round for a price but I always prefer to use places that have a large turnover such as as one for instance hire fleets as they use loads of fuel. I do use whenever possible coal boats if I know them and trust their storage tank. I am at present ccing again with full tanks but will be filling when about half full at wherever I can with a hire fleet if possible.

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had my first experience of diesel bug this morning, luckily on a generator not a boat.

mains power went off (and on phoning was not expected back on within an hour) so I went out to the generator and pulled the starter.

previously the generator has never failed to start on the first pull, this time there was no sign of life. (last run 3 months ago, tank always brim full)

after 10 pulls my arm was getting tired so I grabbed a battery to hook up the electric start (not usually used).

even the electric start failed to get it running (no hint of smoke from the exhaust etc).

popped the fuel line off and could barely get a trickle, and what came through seemed thicker and didn't smell like diesel.

removing the fuel tap from the tank revealed a filter (that I didn't know existed) that was completely blocked with a brown slimy gunge

with fresh fuel (via 2 hoses and a jerry can) the generator started and ran perfectly

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Someone correct me if I have this wrong but I thought diesel distributors just have to declare a minimum amount of bio in the total amount they sell across the board, which means that the red diesel you buy could have no bio content at all or a disproportionate amount.  In other words if certain customers request FAME free diesel then it has to be offset by increasing the FAME content in other supplies.  

If this is right, unless a retailer insists on FAME free diesel they could end up with anything, and presumably the more people request FAME free the more FAME has to be "dumped" on the rest of the market.  

   

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48 minutes ago, Neil2 said:

Someone correct me if I have this wrong but I thought diesel distributors just have to declare a minimum amount of bio in the total amount they sell across the board, which means that the red diesel you buy could have no bio content at all or a disproportionate amount.  In other words if certain customers request FAME free diesel then it has to be offset by increasing the FAME content in other supplies.  

If this is right, unless a retailer insists on FAME free diesel they could end up with anything, and presumably the more people request FAME free the more FAME has to be "dumped" on the rest of the market.  

   

If the diesel is made to EN590, (as far as i am aware all commercially sold diesel is) then it has a maximum FAME  (bio) content of 7%.

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19 hours ago, dmr said:

I find it a bit sad that a lot of canalside diesel sellers have very little understanding of what they are selling. I have asked a fair few if their fuel is FAME free and some of the answers are a bit surprising, but then I am a techy sort of person. There is also a belief in some quarters that diesel and heating oil are one and the same so I would not be completely surprised if a one or two suppliers are not selling heating oil, this doesn't really explain your problems though.

..............Dave

I commented in a previous thread that we need someone on here with recent experience in the fuels blending industry.

I worked on one of the UKs biggestest refinery/Chemical plants - at one stage installing an on line cetane measurement device but I left in 2005 and my knowledge of current practices is now zero. This corresponded with the introduction of ULS diesel (ultra low sulphur). Prior to 2005, we made Gas Oil and it was pumped into tankers with or without red dye and sold to the market - both to road fuels and heating fuels. All within the specs required. Materials were blended into tanks and those tanks sold to the market where specs could be achieved. Yes, it was often the same stuff.

In 2005 (ish) ULS diesel came in and the materials used to make the diesel changed - ie the product from  the hydrocracker was now very valuable and an important part of the blending process. Blending strategies therefore changed and there may have been a split in the 2 products (road fuel and heating oil). However it is interesting to do a bit of a search. Have a look at this site (typical of others).

http://www.fueloils.co.uk/commercial-fuel/commercialfuels/gasoil

They sell ULS diesel as road fuel and gas oil to the heating market - 2 different products. Read what they say on this link. It seems it is the gas oil that is going to marine applications. They dont put red dye in their ULS diesel. If you go to the 'downloads' tab, you can see the specs they are making to - for the ULS and the gas oil. There is not a lot of difference although the ULS is likely to have a higher cetane number but not guarunteed. Note that both products have a 7% limit on Bio diesel content. To answer Neil2 above, there are limits on how much bio can be use in heating fuel as it affects seals and the plastic storeage tanks. If they supply marinas in kent, it will be with red diesel ie gas oil. I wonder how many other local diesel suppliers are workin the same way as this link. It seems the efficient way to do it - ie only 2 tanks needed, one red, one white. It would be very costly to have a red ULS diesel tank.

Having worked in the industry and knowing how they blend road fuels (diesel and gasoline) I am not worried at all about using gas oil in a diesel engine (For a boat) as it meets the minimum fuel specs. I do have a concern though about 'bad' batches - as these do occur. A refinery's objective is to get as much of the 'rubbish' in the barrel of oil into the road fuel and if it can do this within spec then it will. It is quite possible that a batch of gas oil could have something added that makes combustion more difficult but is still in spec. In the OP's case, I think it unlikely that such a bad reaction is down to a bad batch (and unlikely to be linked to cetane number).

 

Edit - cuthound beat me to it - 7% max bio

Edited by Dr Bob
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8 hours ago, dmr said:

Weve done this quite a bit on the forum.

You can still get FAME free diesel on the cut but most sellers don't know how to get in. Norbury and ABC both sell it, and Norbury are cheap so there is no price premium. I think the bio helps the lubricity and detergency, its the low sulphur that degrades the lubricity. The issues are sucking in water, degrading quite quickly, and I suspect the increased possibility of a bad batch, I think bio factories are less consistent than mother nature  :D. The seal thing appears to have been overplayed and only gets a small number of older engines.

.............Dave

The Bio content has a negative effect on the lubrication property of the fuel. This manifests itself in reduced life of injector pumps on engines, and burner fuel pumps on pressure jet burners. The reduced sulphur content causes the carbon to 'drop out' at a lower temperature in vaporising burners, reducing service intervals, but after 12 years since that reduction, we've had chance to get used to this.

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