Replacing diesel water trap - choices choices.

[RJJ]

Hi all

Question please on water trap. I want to replace with (1) a transparent bowl (2) able to drain by hand rather than with socket. Engine is Penta D2 55 hp.

So Force 4 offer:

https://www.force4.co.uk/force-4-water-fuel-separator-fuel-filter.html

Amazon have this for 1/3 the price:

482730 KATSU Diesel Fuel Filter Water Separator Trap Assy Fits CAV 296 https://www.amazon.co.uk/dp/B01M195TDU/ref=cm_sw_r_cp_apa_i_iWUWDbDJZG3X1

Filter spec is the same. Any reason not to go with the KATSU and keep under careful observation initially?

Or there is this one for spin-on, which I understand may be preferable.

R12T Boat Marine Spin-on Fuel Filter/Water Separator 10 Micron 120AT NPT ZG1/4-19 Fit Gasoline Engine and Diesel Engine https://www.amazon.co.uk/dp/B07WDSJDJY/ref=cm_sw_r_cp_apa_i_gcVWDbWMPW39T

Thanks!

 

[pvb]

The Force4 price is very high! The same thing is only £21 at SSL Diesel - https://www.ssldieselparts.co.uk/filter-assembly-single-sfa1-spare-filter-p-898.html

The Katsu product should be fine, these things are very simple so not much can go wrong.

The shallow plastic bowls on these filters can discolour over time. For this reason, some people prefer the glass bowl version (which also has a larger water reservoir). See https://www.ssldieselparts.co.uk/filter-assembly-sfa4-p-709.html for a photo. These have a nylon screw-in plug on the bottom to drain any water out.

 

[Plum]

Hi all

Question please on water trap. I want to replace with (1) a transparent bowl (2) able to drain by hand rather than with socket. Engine is Penta D2 55 hp.

So Force 4 offer:

https://www.force4.co.uk/force-4-water-fuel-separator-fuel-filter.html

Amazon have this for 1/3 the price:

482730 KATSU Diesel Fuel Filter Water Separator Trap Assy Fits CAV 296 https://www.amazon.co.uk/dp/B01M195TDU/ref=cm_sw_r_cp_apa_i_iWUWDbDJZG3X1

Filter spec is the same. Any reason not to go with the KATSU and keep under careful observation initially?

Thanks!

There have been reports here before of difficulties in getting the seals to seal due to poor quality machining on the cheep copies so up to you but any type that uses the CAV296 filter is more challenging when it comes to changing the filter due to the multiple o-rings. If it is mounted in a very accessible position it is fine (my genuine CAV one in a good position has not been a problem) but if it is in a dark restricted access corner a spin-on or drop-in filter is much better.

www.solocoastalsailing.co.uk

 

[pvb]

There have been reports here before of difficulties in getting the seals to seal due to poor quality machining on the cheep copies so up to you but any type that uses the CAV296 filter is more challenging when it comes to changing the filter due to the multiple o-rings. If it is mounted in a very accessible position it is fine (my genuine CAV one in a good position has not been a problem) but if it is in a dark restricted access corner a spin-on or drop-in filter is much better.

There's a cheapish CAV-type filter assembly which takes a screw-on 496A filter element - this has a drain screw on the bottom, but there's no transparent water reservoir.

https://www.ssldieselparts.co.uk/filter-assembly-sfa11-p-718.html

 

[NormanS]

Remember that you will not get any water showing in a water trap filter, until there is sufficient water in the bottom of the fuel tank to be picked up by the dip pipe or upstand pipe. OK as an ultimate safety device, but no tank should have so much water in it.

 

[pvb]

Remember that you will not get any water showing in a water trap filter, until there is sufficient water in the bottom of the fuel tank to be picked up by the dip pipe or upstand pipe. OK as an ultimate safety device, but no tank should have so much water in it.

I agree, I've never ever drained any water out of a glass-bowled CAV filter, but people seem to want the visual reassurance.

 

[lw395]

Remember that you will not get any water showing in a water trap filter, until there is sufficient water in the bottom of the fuel tank to be picked up by the dip pipe or upstand pipe. OK as an ultimate safety device, but no tank should have so much water in it.

Most yacht tanks seem to be designed to leave anything from a litre to a gallon in the bottom of the tank to breed slime.
You will only get water in your CAV with a tank like this if there's a scary amount of water in there, or if the tank gets shaken up in rough weather.
Then suddenly you can get enough water to overcome the CAV. Just when you were depending on the engine.

There are diesel filters for cars which have an electric water sensor in the bottom. If I were fitting out a system, I'd consider one of those.

 

[pvb]

Most yacht tanks seem to be designed to leave anything from a litre to a gallon in the bottom of the tank to breed slime.

My boat has a moulded plastic 150 litre fuel tank which hugs the hull in an aft quarter, so it has a deep corner. In spring, after the boat's been stationary for a while, I open the hatch on the tank and suck about a litre of fuel out of the lowest corner. I put it in a clear plastic bottle and then allow it to stand for a day to settle out. Sometimes there's a couple of drops of water in the bottom of the bottle, never any more.

There are diesel filters for cars which have an electric water sensor in the bottom. If I were fitting out a system, I'd consider one of those.

Also available for boats.

 

[Graham376]

I agree, I've never ever drained any water out of a glass-bowled CAV filter, but people seem to want the visual reassurance.

Neither have I found any water. I don't like the CAV filters, can be real fun to change at sea as I once had the misfortune to do. Much prefer the separate glass bowl followed by spin on which takes seconds to change and hardly any spillage. Plenty of cheap tractor sediment/water bowls on ebay.

 

[lw395]

My boat has a moulded plastic 150 litre fuel tank which hugs the hull in an aft quarter, so it has a deep corner. In spring, after the boat's been stationary for a while, I open the hatch on the tank and suck about a litre of fuel out of the lowest corner. I put it in a clear plastic bottle and then allow it to stand for a day to settle out. Sometimes there's a couple of drops of water in the bottom of the bottle, never any more.

...

Similar here, ever since the first time. We got our boat, it was 15 years old and had 15 years worth of water and slime in the tank.
I have found scary amounts of water in other people's tanks.
Hence we knocked up a polishing rig.

 

[rotrax]

Check out the Chinese Racor 500 copies on ebay. The Racor patent has long expired, so anyone can use the technology.

At around 50 quid they are a bargain, and being top loaders the filters can be changed easily and cleanly. Easy to just drain the bowl too.

Genuine Racor elements and seals fit. I have just installed one on my fuel tank return as a permanent polisher, with a 10 micron element.

 

[NormanS]

Is there any point in installing it on the return? Presumably all the fuel in the return has already passed through a couple of filters already.

 

[RJJ]

Thanks everyone for the excellent tips

 

[Stemar]

I had a love hate relationship with the O rings on CAV filters ever since I got the boat until I had a bouncy passage when low on fuel and the engine died just short of the entrance to Portsmouth Harbour, resulting in a rather fraught entry under sail. Within a very few days, I got a couple of spin-on fuel filters from a car breaker, added a bit of plumbing and taps (ASAP is your friend here), so I can now switch filters in seconds and, most probably, change and prime a filter under power. The whole job probably didn't cost more than £50. One of the best investments I made on the boat, because, of course, now I'm ready for a blocked filter it hasn't happened. I changed the filters last year, after about 10 years because they were getting a bit rusty.