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Wednesday, January 5, 2011

Racor Redundancy

When we got Eolian, the fuel system was a bit of a hodge-podge.

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
The steel canister filters were a poor design - you were virtually guaranteed to spill fuel with them when changing an element. And they were rusty. So I pulled them out.

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.)

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