Primary Path Problem (Fuel Filters)

[theway]

Ok, In the image (below) is the setup I have inherited on my boat. I first observed the system with all 3 valves open. Instructions on the boat say "open 2 & 3" or "open 1". I currently have only "1" open because the mechanic suggested that the pump should not have to or would not like to pull fuel through two filters.

I have read that (and mechanic suggested) that the plumbing should allow one or the other filter so they can be switch while the engine is running. So the questions are...

1: Is it ok to go through two filters and then switch to only the second one when the first is dirty?

2: Should I re-plumb to be able to toggle between filters? (so I can switch filters while the engine is running)

3: Is there something in the current setup that I'm missing? (because the owner (few owners back) who did most of the work on this boat seemed to know a lot and did a lot of nice mods)

4: Is there another way altogether in your opinion?




thank you much,
austin

[motion30]

You should be able to pull tru each filter indiviually or how will you know when one is clogged?

[noelex 77]

Some owners use 2 primary filters in series a coarse one say 30 microns and a fine one say 10 or 2 microns. This may have been the thinking behind the original pluming.
Is the secondary fuel filter on the engine hard to get at and change? This is often the incentive for this type of set up. The finer primary fuel filter means the engine mounted secondary filter is redundant and should rarely need changing.

A better use of 2 primary filters IMHO is to keep them both 10 micron and be able to switch between the 2. So if 1 clogs you can keep the engine running. This would require a change in pluming.