Fuel gauge NOT accurate: how to calibrate?

[Mariner]

Lots of good info here. Sight gauges are a good idea, but would require some welding with the tanks empty and wouldn't be cheap. Might be tough to get the master to approve that expenditure. There's access to the top of the tank, but no easily removable access to the inside of the tank to take soundings, so a dipstick is out of the question for now.

We do keep a detailed fuel log, but we run at drastically different speeds and fuel consumption rates based on what we're doing, so a log is only so reliable. Short of logging every single run, I suspect this is not the end-all solution.

I think the most reliable thing would be to get the gauges fixed or properly calibrated. That, combined with a careful watch on the log ought to be good enough for the time being (though I'd still like to install sight gauges some day).

As for restarting, it would have been easy had I known the procedure ahead of time. It is not necessary to bleed the system, but it is necessary to prime it. Also, we have this recurring problem of the batteries not having quite enough juice to kick over the starter. It takes only a few minutes of leaving the house and start batteries combined with no charging source before you are unable to start the engine. Since the generator was also out of fuel, we had to first get the generator primed and started then wait for it to charge the batteries back up before we could then prime and start the main engine. Although I am familiar with diesels, I was hoping that I would still be able to just crank it over and restart it as I have done with other engines in the past, but it did not work. Once I primed the system, it was pretty quick to start. Had it happened while not alongside a dock (we fortunately drifted right into an open slip), it could have been a problem, as it took me a good 15 minutes to get the thing back up and running.

I would never have let the thing get under 1/4 tank if I had had accurate information.

[jgilman8]

Can anyone tell me where to find a schematic for a 27 foot Albin with a 6 cyl Isuzu diesel.. the model year is 1990.

Specially I need a schematic for the fuel gauge system. There are twin roughly 35 gallon aluminum fuel tanks, port and starboard with a single fuel gauge on the dash with an "A" "B" switch, a single selector switch for port or starboard tanks.

Thanks so much,

Jeff
jgilman8@gmail.com

[jleonard]

I guess I have been lucky. My last two boats have had normal float gauges and sending units and they both were so accurate it is scary. I can predict within 10% how much fuel I can take on.
I also have sight gages on my current Albin. I hate them and never use them. The tubing has gotten a little stained over the years, plus who the H wants to crawl into a hot engine room while taking on fuel? Yuck! Did that on a friend's boat and it's not for me.
Of course with 360 gallons of fuel capacity and an engine that burns less than 2 gph I certainly don't need a flowscan unit.

[Mariner]

To follow up, we ended up installing a Tank Tender tank monitoring system. It is very accurate, but, seeing as we didn't have room to install it at the helm, it is not as convenient. I've since come to the conclusion that simply replacing the fuel gauge with a new Teleflex one would probably solve the problem. I've just never gotten around to it.