Diesel Fuel Hose

Brian K

Member III
I've had problems over the years knowing when my fuel tank is actually full. Yes I have a gauge and it does work. It would be nice though to see when the tank is full and I was wondering if it would be possible to replace the diesel fuel filler hose with a thick clear plastic hose. Or maybe just replace the last section that is verticle with a clear hose.

Another thought would be an inspection port with a Lexan or Plexiglas cover.

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Maine Sail

Member III
There are no clear hoses that meet the permeation or fire requirements for a fuel rated hose.

Fuel fill hose should be marked USCG and J1527 with the year of manufacturer and is most often type A2 in 1 1/2" diameters for boats in this size range. Fuel hose for inside engine compartments should ideally be type A1-15..

You'd be safer to add a sending unit and fuel gauge.


Sustaining Partner
It is very common in aviation to have a sight tube, with gradations marked on it, to indicate fuel level in the tank. Now maybe aviation is less concerned about fuel leaks or maybe they figure that a fuel line in the cockpit is the least of your problems if something goes wrong. I can't tell you what to do with your boat, just that aviation suppliers may have what you are looking for, clear plastic fuel grade hose.


Brian K

Member III
That's what I expected,,, strict guidelines for acceptable fuel line hoses. But the aviation hose is an interesting alternative and it's also probably more costly than "marine" equipment. Thanks!

Brian K

Member III
That's what I installed a couple of years ago. I still get a lot of needle movement in the gauge. The real problem I have is knowing when the tank if really full. Since I usually fill via a hand pump there is no auto shutoff feature and invariably I end up spilling a little fuel over the side. It's amazing how a few drops of fuel can create quite a slick. Anyway, once the tank is "full" it seems like it can actually take more after it settles for a bit. Maybe my vent line is plugged and it's not being efficient with letting the air out of the tank. Thanks Loren.


Contributing Partner
I still get a lot of needle movement in the gauge.
The new fuel tank I installed a couple of years ago came with a WEMA sending unit and it even has a fair amount of fluctuation when the tank is less than full. It is also kind of hard to tell when the tank is actually full as the needle goes beyond the top of the "full" mark on the gauge. I suspect that the tank is not quite full when the gauge is right on the "full" mark. I usually let the tank get down to 3/4 then buy 5 gallons of fuel and that puts the gauge back over the full mark. The original specs on the 30+ indicate the tank capacity as 25 gal., but the drawings I got from Berry Sheet Metal dated 1983 show it as 19.5 gal. I checked the old tank when I removed it by filling with water and it only took about 19 gal.
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Stu Jackson

C34IA Secretary
The most cost effective way to figure your fuel needs are to analyze your fuel consumption. Marine fuel senders are notoriously horrible, partly because of the neanderthal fuel senders and partly because of the fact that many if not most of the fuel tanks on boats are assymetrical. They ain't your grandma's car fuel tanks and gauges.

Spend some time to document your fuel use and you can refill without spilling by knowing what to expect BEFORE you start pumping.

Our M25 engine uses 0.493 gallons per hour for the pats 13 years. Our spreadsheet makes it easy.



Member II
I have a theory, if your tank is like mine on a 32-3 it is has a large flat top which means that the top two inches holds several gallons of fuel The vent is on the back. If the top is not level there will be air trapped in the forward end. The result is that the tank holds several gallons less (in my case 22 gal). I'm thinking of replacing the tank since there is some corrosion and maybe placing two vents, one aft and one forward. It doesn't help that I'm usually standing in the cockpit making matters worse since it tips the tank even more. I really should put a level on the tank but I'm not near the boat now.