Lucas CAV seperator/filter

[MoodySabre]

VP 2003 engine - 26 years old - original SS tank. No issues. It has the old style seperator, a round bowl with a plastic screw in the bottom.

Confession first: At the end of last season I ran out of fuel. Topped it up, bleed the system at the screw-on filter and off we went. A few run outs since and all's well.

Reading a thread somewhere else I decided to look at the bowl with a torch behind it. It is hard to get to and the heating pipe goes right across the top of it - I have paid it scant regard in the last 8 years and never changed any filter there.

Shock horror - there was a third of very dark and some 'strings of blackness' down the sides. So I drained off the gunk. Black bits presumably from the bottom of the tank. However the 'strings' remain.

I can't get to it take the bowl off (presumably there are screws in the the top). Do the modern ones have a screw off bowl? Are the fittings likely to be the same or have gone metric?

A local engineer at £35 an hour sounds like a bargain for that contortionist job.

 

[Hadenough]

Are you saying that you haven't changed the fuel filter in 8 years! If it's that hard to get at I'd be moving it ASAP, you really should be able to get at it at sea. And if you can see the black strings in the glass bowl you have a seriously blocked filter.

 

[MoodySabre]

I am embarrassed to say this is true. The bowl was clear at the beginning of last season. I did a lot of motoring last year due to headwinds for a month in Holland perhaps 200 hours or more. This included two or three fill ups in Holland.

OK maybe this shouldn't wait until the winter.

 

[Hadenough]

I've found that the glass bowl will show you if there is any water being separated but the filter in doing its job stops the black gunk getting to the bowl. Last boat had a dirty tank and I used to change filters twice a season, never saw much in the glass bowl but was usually horrified at what the filter had - er - filtered. By the way despite it's many fans I hate the CAV filter and am convinced that the filters are getting poorer and poorer in quality. Have a look at a screw in Racor if you plan on changing it. Best of luck.

 

[Pete7]

Roger, I think this is the standard water separator for a M31, there is no filter inside, just a plastic cone. I replaced mine a couple of years ago because the original plastic became dark through diesel staining. Didn't do any good, the new one is now the same colour, however, they are available from IM Supplies.

http://www.imsupplies.co.uk/catalogsearch/result/index/?q=fuel&submit_x=0&submit_y=0&p=9

If you have stringy stuff in the water separator then I have bad news for you. I did too and this is what I found inside the fuel tank (Post 9 onwards). If you have a stainless steel tank, then that is posh, standard is painted mild steel. the good news is with marigold gloves and a paint scraper it will only take an afternoon to sort it out.

http://www.ybw.com/forums/showthread.php?378623-Diesel-Bug

Pete

 

[Hadenough]

Ah-ha! Different to what I imagined. Even so I'd move it and look at an upgrade.

 

[tillergirl]

I am embarrassed to say this is true. The bowl was clear at the beginning of last season. I did a lot of motoring last year due to headwinds for a month in Holland perhaps 200 hours or more. This included two or three fill ups in Holland.

OK maybe this shouldn't wait until the winter.

Roger

At the beginning of last season when I changed my filters, I found some black threads around the filter, although the bowl was clear. I shocked the contents of the tank and saw no further evidence. However, during the winter I opened up the tank and found this



Drained down, this crud was at the bottom.

[URL=http://s217.photobucket.com/user/rgaspar_album/media/P1000824.jpg.html]

I cleaned up the tank and since my tank is far too big and therefore I have a lot o disel unused each year, I have installed a fuel polishing system. Now my tank looks like this:

[URL=http://s217.photobucket.com/user/rgaspar_album/media/P1010044.jpg.html]

Of course I do have a MAB where it is possible to get to the tank easily!

 

[MoodySabre]

Thank you all for those tales of horror. I have a fairly full tank so will run it down before considering the job.

Pete7 - did you make up your own fuel extraction kit?

TG how did you empty your tank?

8 years of ignorant bliss is coming to a close......

 

[tillergirl]

Thank you all for those tales of horror. I have a fairly full tank so will run it down before considering the job.

Pete7 - did you make up your own fuel extraction kit?

TG how did you empty your tank?

8 years of ignorant bliss is coming to a close......

Just got some 25 litre cans and pumped it with one of those cheap squeezer hand pump things. Got it down to black crud image above. I have two inspection hatches in the top of my tank which are easy to remove. Once the tank was clean, I used the new fuel polishing system to clean the fuel before it went back into the tank

 

[Pete7]

Roger, yes made up of a CAV filter and a faucet fuel pump off e bay. The original idea was to polish the fuel in the tank a couple of times a year, because my fuel tank was spotless or so I thought. Fuel take off was the sight gauge tube and returned via the filler.

So for several years I did, CAV filter was always clean, so no problems. Volvo 2003 was a sod to start but put this down to the engine.

After finding the bug and it was only a tiny amount in the fuel separator each year, the tank was cleaned and given a serious dose of Marine 16, previously used Fuel Set on the boat. Now that I have about 10 hours of motoring post tank cleaning the engine starts much more easily, there is a lesson in this somewhere.

Would be worth replacing your fuel filler o ring, its actually a gasket and they are available from Force 4 on line for a couple of quid because water gets into the tank somewhere.

Link to fuel pump type:

http://www.ebay.co.uk/itm/UNIVERSAL...arts_Vehicles_CarParts_SM&hash=item25856b33b2


Pete

 

[MoodySabre]

Well at least my engine starts very easily!

I see you did this crouched in the locker. I have a holding tank done there. I'm not built for lockers.

Thanks again.

 

[Graham_Wright]

Link to fuel pump type:

http://www.ebay.co.uk/itm/UNIVERSAL...arts_Vehicles_CarParts_SM&hash=item25856b33b2

Pete

I have one of those. If the output is blocked, does the pump still run? (Mine is on the fuel tank and only run until the engine pump takes over.)

 

[Pete7]

Graham, if you mean the output on the tank no it doesn't. the pump makes a right racket until it fills up with fuel.

Pete

 

[Pete7]

I see you did this crouched in the locker. I have a holding tank done there. I'm not built for lockers.
Thanks again.

In that case I would be tempted to have the fuel tank removed to make cleaning easier. You might want to replace the water separator at the same time or at least move it.

Pete

 

[MoodySabre]

In that case I would be tempted to have the fuel tank removed to make cleaning easier. You might want to replace the water separator at the same time or at least move it.

Pete

You wouldn't get tempted because the holding tank would have to come out too.
Thanks for your replies. A weekend afloat to cogitate beckons.