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Diesel filtration etc


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A query in three parts, please.

 

My no.2 son was towed home by the Coastguard from Hooks Bay yesterday. No wind to sail and his Racor separator was gummed up with crud. The culprit would seem to be his deck filler cap which is not sealing properly and has been letting rain water into his fuel tank which finally reached the bottom of the fuel delivery pipe to the engine with predictable results.

He has always used a diesel fuel conditioner and has been particular with regard to engine maintenance. As of writing, he is in the process of completely emptying the tank via the drain plug and one of those vacuum suckers but has no means to inspect the inside of the tank.

 

(1) He will of course change all his filters but is there anything he should do prior to filling the tank with fresh diesel? I am envisioning poking a spray bottle wand into the tank and spraying the walls with some product or other...?

 

(2) As a result of his misfortune I am thinking about my own fuel system now. My engine has 2 fuel filters with the one closest to the tank being a CAV unit with a bowl on the bottom. The engine burns 2.2 litres per hour. Is the CAV automotive type filter separator unit sufficient to remove any water from the fuel or should I mortgage the house and buy a Racor unit?

 

(3) When we bought the boat in Holland it had a bottle of some American made diesel additive on board. We have used it all up and can't get the same stuff in France. Are all these various types of diesel fuel additives compatible with each other?

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Thanks CH. I haven't seen the problem my son has. He says the fuel taken from the separator is whitish looking but has the same viscosity as healthy diesel - no stringy sticky snot in it. So presumably not diesel bug but water in suspension in the diesel by virtue of the fact that he always uses an additive.

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Where did he buy his diesel from??  additives should be compatible with each other, replace filler cap.

We have had water in fuel in some of our trucks that have filled up z truck stops,tanker been later getting to station and pump is suppose to switch off when tank reaches 1000lts due to water table,

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Yup: I always seem to get just a little bit of moisture laying in the top of the through deck. Not much you can do about that and with condensation added it builds up..

I have found that if I vacuum the tank every time I do an oil change then I seem to collect no crap on the filter and most definitely no water in the glass bowl.. All I waste is 2-3 litres of diesel :)

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Chris, the Cav filter is fine, that's what I use. One thing though, if it's the one without the glass bowl (alloy instead) replace the bowl with glass. You need to be able to see inside! It should be checked daily.

Imo any tank without an inspection port should be modified...

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As was said, there is water IN the diesel you buy. Not sure how much, may depend on service station but with regular use and the fact that the fuel is continuously being mixed through cornering and breaking, its generally not an issue for most road users. Not the same for a lot of marine users who sit about in marinas. Over time the water component seperates and we all know the rest! I believe rigging up your own fuel "scrubber" is the way to go. A pump and filters cycling fuel from and to the tank on a regular basis keep the shite and water out.

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No.2 son is cleaned, refiltered and refueled and on his way out again so we will see how he gets on. Hopefully he doesn't have to bother the Coastguard again.

 

IT, my bowl is the glass type. Even so, I find it difficult to see inside the bowl where it's located within the dark confines of the engine room. I have gotten into the habit of draining the bowl into a glass jar and taking it up on deck where I can see the contents properly. Not every day though.

 

rmiker, by vacuuming are you referring to using one of those oil change sucky bottles where you poke the hose down the dipstick pipe? I used one of those bottles on the H28,twice a year, putting the hose down the filler pipe until it hit the bottom of the tank and drawing up a few litres. We don't have such a bottle on the canal boat but use the tank drain to let out some fuel into a bucket. I guess that does the same thing?

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rmiker, by vacuuming are you referring to using one of those oil change sucky bottles where you poke the hose down the dipstick pipe? I used one of those bottles on the H28,twice a year, putting the hose down the filler pipe until it hit the bottom of the tank and drawing up a few litres. We don't have such a bottle on the canal boat but use the tank drain to let out some fuel into a bucket. I guess that does the same thing?

Yup: just the vacuum oil pump.. Best thing since sliced bread IMO.. Well I wish the designer/builder of my tank had put in a socket for a drain valve because where the tank is situated it is very accessible and so would have been usable aka easier. 

However the vacuum pump is also very easy as long as I do it on a regular basis so I am not going to shag about modifying anything now..

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After getting rid of water in diesel I installed a rubber primer hand pump inline to the Racor filter. This pump can prime and push air out of fuel line very well, much better than the built in lift pump on Yanmars. This is normally used on outboards but are a godsend on small diesels for quickly bleeding air out.

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Why is Diesel additive so expensive??? I'm guessing that the cost of the chemicals needed would be minimal, epsecially given that the volume of the product containers available for sale varies from 100cc to 1000cc. Somehow, I feel the high price is just because they can, and the down side of not using can be irksome! (very)

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Funny thing this diesel additive,never remembered the old man putting it his launch,300 gallons in the 70s nor when he had his yacht for 8 yrs and he was a marine engineer,so why are we putting it in?to tight to fill tank?

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CAV messy horrible things. Changed ours for Racor.

Grotamar additive from Smart marine or Transdiesel is good but also not cheap.

That a my impression of the CAV Delphi units as weĺl. IT says it's important to check/drain/clean the bowl regularly as part of your fuel management, and he is right. I have been a bit lax here because the CAV unit is difficult to work with. Have you noticed that the Racor unit is a lot easier in this regard - worth the extra money?

Steve, there must be a difference if you base it on price. Some additives are cheap and others eye wateringly expensive. Do you get what you pay for?

Big problem for me. Fuel additives are a prohibited item in airline baggage and in France I dont rdcognise the brands and I can't read the labels.

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Funny thing this diesel additive,never remembered the old man putting it his launch,300 gallons in the 70s nor when he had his yacht for 8 yrs and he was a marine engineer,so why are we putting it in?to tight to fill tank?

The water is IN the fuel we buy. Is it a new thing? Not sure what or if there is a standard of quantity of distillate from the 70's to today but fact of the matter is, fill your tank and there will be water in it.

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