There were the two main tanks, of course, port and starboard. And a 45 gallon day tank.
On the engine was the final fuel filter, a 10 micron one that looks like an oil filter. Next inline upstream was a Racor 900 gal/hr large filter. Upstream from that were a pair of steel canister filters - the kind where the bottom screws off, full of fuel, to change the filter element.
And valves. Enough valves to control a nuclear power plant.
After experiencing a few "unscheduled stoppages" (as the Previous Owner termed them), I tore into the system. Here is what I found:
- The 30 micron element in the Racor was clogged
- The steel canister filters had no elements in them
Next , I bought a second Racor 900 - yes, this is way, way more flow rate than our engine needs (we burn a little less than a gallon/hr at cruise), so the centrifugal water separating feature of the Racor was not really going to function, but the huge filter element would absorb a *lot* of gunk before blocking off. I liked that.
I installed the second Racor right next to the original, with valving such that I can switch filters while the engine is running. The valving will also isolate the clogged filter so that the element can be changed under way.
Finally, I installed a second fuel vacuum gauge in an easy-to-read location so that we can easily monitor the need for filter change-over.
(I also re-plumbed the entire fuel system, removing a third of the valves, but that's hardly a small boat project.)