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Reply To: Fuel Problems When Rolling

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David Babsky

Oh: how lovely to see Dr Vic in the reply above! We have Dr Vic’s previous Nauticat, and love her! (..and Dr Vic, of course!)

A problem which I found fairly early in our ownership of Nautilia was that in “..short steep beam sea..” or similar bouncy conditions, muck from within the fuel tank(s) (..though Dr Vic had kept them scrupulously clean!..) – or in that bladder – gets all stirred up and can easily clog one, or more, fuel filter(s). So always have extra filters on hand, and – as Dr Vic says – have fuel tank(s) well filled, so that the end of the fuel tube is always well immersed, whatever the boat’s angle.

If the low-pressure lifting fuel PUMP diaphragm has not been checked for a year or three, do check that the rubber diaphragm has no cracks or holes and hasn’t perished.

I found that when our fuel tanks showed ONE THIRD or less full, the fuel inlet pipe could easily suck in air, and that there wasn’t a USABLE one-third-of-a-tank of fuel still available, and so I never after let them get lower than one HALF full. (Discovered that during entrance to Dartmouth, among the rocks(!) ..and then again with Dr Vic on entering Dover at night!)

I also removed both fuel-gauge senders/sensors, and replaced them with much more reliable and accurate vertically moving floats, and calibrated those so that I knew that the readings on the electrical fuel tank gauges were properly accurate. (The originally-installed senders used a hinged arm and a fragile carbon electrical track on their arms, and the carbon had cracked, so that readings were unreliable. I installed two more reliable vertical “reed switch” senders similar to these: )

I don’t know how “common” a problem this is, but I’d say (1) be sure to put ‘Marine-16’ or similar diesel-bug biocide in your tank(s) each year; (2) be sure that you know how ACCURATE your fuel gauges are; (3) keep tanks close to FULL, if poss, so that the inlet suction pipe doesn’t suck in air when the boat heels; (4) check at least annually your fuel filters and fuel pump diaphragm.