Have you thought about buying a standard spin on fuel filter head off Ebay? We bought one that is standard fit for a Merc truck. Brand new but cheap. Filters are about £10. It's a 5 micron high performance filter. It's large and I have it mounted remotely on our generator. It makes access to change it simple. I have no other fuel filter fitted to the generator. The one big high performance filter does it all
You can remove the engine fitted one. You won't need it. Most spin on fuel filters come with a drain on the bottom so you can still drain water. None of the complexity and risk of nipping a seal and getting an air leak that is so common on the CAV type combined filter and bowl. When you have a contaminated fuel filter the easiest thing is to spin one off and spin one on in an easy remote location and you can be back in operation in a couple of minutes. Did this on my old boat main engine. We did just that when leaving a busy harbour and the engine revs dropped. Blocked filter. Quicker filter change than a Quickfit fitter
Don't know what the manufacturer's spec is for your engine but my VP secondary is a 5micron and I have a Racor 500 primary with a 10 micron element. I would certainly not dispense with the secondary filter as if you look at filter specs they will say something like 5micron at 90% efficiency so some particles greater than 5 will still get through so a second filter, even if the same micron rating, will still be better than just one.
A single filter with 5 micron efficiency at 90% is an excellent level of filtration. Why add a second filter if one can do it all? I found my paper second filter never got dirty. It was better to remove it to reduce the number of possible air leaks in the system. Single fuel filters are commonplace on diesel vehicles
you can buy CAV / Delphi spin on filters (HDF496) but it will need a replacement head too. They are a tad cheaper than Mr Racor's offerings.
Because a £5 filter is cheaper than sorting out an issue if your single filter fails.
Have you ever seen a single filter fail? It doesn't happen on diesel vehicles fitted with single filters. Super easy to spin a new filter on in an emergency and know you only have one to do
So what do you do when you damage your secondary filter and the dirt has got to your primary and you need to change it. You might let dirt through. It's a silly argument. I had a single filter set up on my last boat using the same spin on filter as a transit van. Transit vans tend to move about rather a lot as well as boats. It simply works fine. My generator has a single Merc spin on filter. Works fine. It's so oversized being designed for a 5 litre engine it has massive dirt holding capacity. The generator is 500c. When I remove it any upstream fuel runs out of the filter head and flushed dirt away. No risk of dirt going downstream of the filter. It's up hill to the engine. The main reason why I removed the filter on the engine was to simplify the fuel system. I was chasing air leaks for fun. The tiny filter unit as fitted to the unit was fidly and unnecessary given the Merc filter head so I took it out of the system. Been like that for years now and runs great. I also converted to electric fuel pump as the mech pumps are lousy.
Plum, many thanks this just what I wanted to know - I'll fit a 10 micron on the Racor.