Every year I replace the small Yanmar diesel filter on my 2YM15, but have never changed what I presume is the primary diesel filter/ water separator in the bilge. I have drained a little diesel from the flanged nut underneath. This looks like a CAV 296 filter top but without an obvious glass water separator. Is there a specific type of filter/replacement for this and is this something that is routinely changed?

Yes, definitely. The 296 is probably doing almost all the work of filtering. The cartridges are cheap and are worth changing fairly often although there's lots of scope for argument about how often!

Martin

P335/50

Hi Martin,

Thanks for replying. Presumably these come with or without a water separator, as I can't see any glass bowel at the bottom. Do I just undo the wing nut at the bottom and ease out the cylinder - if there is room!!

Bob

Sorry "bowl" - comes from a medical education!

Bob

Hard to be certain as there are a lot of different filter bodies that take a 296 cartridge. Usually you undo the bolt in the centre of the lid but I can't promise that is how yours works!

Bob,

I recommend you replace the fuel filter annually as it is your main in-line defence against diesel bug. I suggest you first enclose the filter assembly in a waterproof plastic bag, then undo the central top bolt which will release the filter and lower bowl. You can then replace the filter and add a clear bowl (mine is plastic) if you wish. See attached photos of my original filter assembly, the diesel bug blocked filter and replacement filter and bowl.

Carl

P285

Hi Carl,

Many thanks for this. Your photos are great and explain the whole arrangement. My problem, apart from access, was not understanding that the black unmarked middle part of the assembly was a replaceable filter body.

I have now replaced the filter (and it looked as gungy as yours) with a CAV 296 equivalent from the local garage. In the end it was easy to unscrew the central bolt as advised and drop the filter. I used a halved milk bottle on its side and hydrophobic oil absorption fabric underneath to catch the diesel, which proved effective. I had remembered to switch the tank off! I had been warned about diesel possibly siphoning back via the return pipe, but this did not happen. The only small difficulty was removing the upper seal from the top housing, which in the end was accomplished with a needle.

The filter refilled easily by gravity, though the bleeding bolt with its copper washer was a little tricky to close. I have kept the metal water separator, rather than sourcing a plastic one.

Apologies for the long description, which is really for my benefit for next time.

Many thanks for your reply,

Bob

TEAL 285/74