Posted: Sun Nov 21, 2010 12:00pm

I have a water trap fitted close to the outlet from the diesel fuel tank, can the water be drained off from the trap without removing the whole unit from the system, there appears to be a wingnut on the bottom of the unit, is thia purely a fixing or is it a drain point? can anyone enlighten me? Sorry I am not aware of the manufacturere of the unit. Duncan

Posted: Sun Nov 21, 2010 9:57pm

As you are probably aware that question stands as much chance of getting a definitive & correct answer as asking what colour the ladies hair will be sitting in the third seat back on tomorrow morning's bus. If this is a very old boat I suspect it may be to operate an internal "scraper" to remove sediment for the strainer surface and if I am right it is not really a water trap as such. The best thing for you to do is to email me a good clear picture to Tony@TB-Training.co.uk. Then I might be able to identify it and give you a fair answer. You have to understand there is very little standardisation and lots of home made "improvements on boat equipment, especially inland boat equipment so what you have could be anything. Sorry Tony Brooks

Posted: Mon Nov 22, 2010 9:44am

Suspected that might be your answer. Unfortuneately I am sitting 180 miles from my boat at present so a photo is out of the question at this time. i can tell you that the boat is only 3 years old. I will try to contact the builder, ironically the detail of this item is about the only thing I wasn't supplied when tyhe boat was purchased. can you at least confirm that there are traps on the market that can have the collected water drained off in this way. Thanks

Posted: Mon Nov 22, 2010 10:46am

Ah, now we get more information - its probably only 3 years old so that all but rules out type of pre-filter I was thinking of. Now I need more information. 1. Is this a true wing nut or a bolt with a ovalish spade end for you to grip or is it plastic - if so what shape. 2. Rough dimensions and a description of how the body of the thing is made up - is it a large body fitted directly into the top mounting bracket or is the body made up of more than one part - sort of sandwich like. If so what is written on the top bit just below the top bracket. 3. Exactly what is in the top right in the centre - if anything. Once I know that we have some chance of identifying it. Tony Brooks

Posted: Mon Nov 22, 2010 12:44pm

It has an inlet and outlet running across the top, below which is a 3" diameter solid metallic bowl. It appears to be one piece. It is difficult to determine the nature of what feels like a wingnut, as it is underneath, at the bottom of the bowl and without a mirror is out of sight. The unit is not easily accessible other than from the top. As you can tell I am trying to avoid having to disconnect the unit from inlet and outlet, to avoid diesel spilling everywhere. Is my best policy just to unscrew the nut and see what transpires?

Posted: Mon Nov 22, 2010 2:06pm

This sounds like a CAV/Delphi sedimentor and if the "wing nut" is in fact a spade headed screw and is slightly offset from the centre of the bowl base it will be a simple drain plug. However if you undo the nut and the fuel level in the tank is below the level of the screw you will allow air into the filter. This will require bleeding out. Modern engines tend to be self bleeding as long as you have enough battery charge. Older ones need a manual bleed procedure so do not undo the drain until you either know the fuel level is higher or you know how to bleed your particular engine. At fuel filter change time this unit would ideally be stripped and cleaned. This is the first place you may find evidence of fuel bug. Tony Brooks

Posted: Mon Nov 22, 2010 3:50pm

Tony, Thanks, I will give it a go when next on the boat. The tank is full (the trap is below this level), and I am using Marine 16 to try and keep the bugs at bay, so hopefully all will be well. Thanks once again for your invaluable assistance. Duncan