Another tale of Fuel filter woe

[Scillypete]

Whilst bringing our recently purchased Prout back we had some problems with the diesel, no surprises there the boat was a long time waiting for a new owner, but after changing filters we could not get it to prime. The bleed screw on the CAV had been covered in ptfe tape, which we were disgusted at and then dismissed after fitting a washer. No matter what we tried we could not get the filter to stay primed and we could not get rid of the air in the system. Eventually we just bypassed the filter to continue on our way and relied on the engine filter only, which was fine.

Since getting back I have tried many different ways to get the filter primed and eliminate the air but all to no avail, then I read a post on here and someone suggested an in line 12v fuel pump . . . aha thought I this will be the solution to all my troubles, so bought one, fitted it and connected all the lines up through the CAV filter, switched it on to prime the system which it did in fairly short order, closed the bleed screw only to find there was still a good spray of fuel coming from a crack in the bleed screw housing, a crack that was not visible and that I would never have found without putting the fuel under pressure.

Now ordered a new CAV water trap filter unit and should hopefully finally solve the problem.

 

[KellysEye]

Problems with CAV filters come up often change to Racor. If you think you have a fuel leak use talcum powder to find it, I've given details of where to put it in many other threads.

 

[ghostlymoron]

Problems with CAV filters come up often change to Racor. If you think you have a fuel leak use talcum powder to find it, I've given details of where to put it in many other threads.

Considering how many boats are fitted with CAV filters and how few are fitted Racor, I don't think the number of faults reported is very large.

 

[vyv_cox]

The talcum poweder method would not have worked because the leak was in an area of the pipework under negative pressure. It was only found by converting it to positive pressure. With a tank in the bilge and a lift pump drawing fuel upwards this will always be the case. It would work for me because the tank is high in the cockpit, supplying the filter at positive pressure. This has its advantages but also its disadvantages, as we found when we had a bilge full of diesel.

 

[alan17]

The talcum poweder method would not have worked because the leak was in an area of the pipework under negative pressure. It was only found by converting it to positive pressure. With a tank in the bilge and a lift pump drawing fuel upwards this will always be the case. It would work for me because the tank is high in the cockpit, supplying the filter at positive pressure. This has its advantages but also its disadvantages, as we found when we had a bilge full of diesel.

Like most things in life there are pros and cons! Boating probs are no exception