Need help - fuel level mystery

[sdubnoff]

I am on my first tank of fuel in my new Cutwater. When I left the dock this morning I saw that I had about 40 gallons. When I tied up at my destination, after a twelve miles, there was a "fuel level alarm" on the Volvo panel and it indicates that I have zero gallons. The Garmin level agrees.

Now I don't believe this and suspect something is amiss with the tank level sender , and I cannot figure out an independent way of checking this. When I look at the top of the tank, it looks like there is a regular float sender there. Does that go out over the NMEA 2K network? Is the Volvo measuring fuel consumption independently? Is there anything I can do to inspire enough confidence to make the trip home?

Many thanks in advance ,

Steve

 

[RProffer]

To play it safe, I would refuel before I went anywhere. Do you have a fuel burn rate chart - A chart that tells you what to expect for fuel burn and speed at certain RPM's? The manual for your engine might have such a chart. If you do not have a chart and cannot obtain one, then I recommend you create one, and in the mean time, take it easy.

 

[knotflying]

I am not sure which Garmin unit you have and if it syncs with the Volvo display, but as far as setup goes you need to set what your fuel capacity is and then fill the tank. Each time you add fuel you need to enter the amount of fuel you added or if you top off just press filled tanks. Then the unit will calculate your fuel remaining based on your fuel flow. There should also be a setting for the alarm to warn you about your fuel remaining and this can be set at your desired level.
As RProffer suggested, I would put fuel in to play it safe and then when you get to a place where you want to buy fuel at the right price you can put all your settings in order. After that I would monitor things to make sure it is not another issue such as a float, or wire connection issue.

Let us know how it works out.

Mike Rizzo

 

[jimschu]

Knotflying is right on with his advice. We have the R-29 and once I determined the accuracy of the fuel usage, I refill to within two gallons of full. That way I never have to worry about the diesel burping out the fill pipe or the vent.
Good luck

 

[sdubnoff]

I opened one of the unused plugs on top of the tank and stuck in a wire coat hanger for a dipstick. It looked like there was about an inch in the bottom of the tank. I was not going anywhere so I called up my friendly Vessel Assist guy who brought me five gallons of diesel in a can. The amazing thing is that the display then said I had more than forty gallons!

We are going to travel at slow displacement speeds to the nearest fuel dock and fill it up. We should make it easily with the five gallons we just added. I will then fill it up and try to resynchronize the Garmin. But I still do not understand at all how it went from zero to over forty on one can of fuel. Something is amiss!

Thanks to all,

Steve

 

[Spinner]

This topic was discussed at the Points North seminar of the past two days. To summarize, there are two ways that fuel is measured: as fuel burned, which is quite accurate, and from a float sensor in the tank. The problem with depending on the float sensor is that when traveling, the bow is up, the fuel is at the back of the tank, and therefore the float sensor will indicate more fuel than is actually in the tank.

The previous poster described the preferred method, which is accurate.

 

[knotflying]

The float gauge is the most inaccurate method of knowing your fuel supply. As Spinner said, when you are running the fuel is on an angle and your readings will always be very inaccurate, full when running and if you have little fuel empty when at idle. The best method is as I described above.

 

[knotflying]

That way I never have to worry about the diesel burping out the fill pipe or the vent.
Good luck

I installed a vent whistle. Very easy and inexpensive. About $20.00 with shipping. I installed it about a foot below the vent. It took me about 15 minutes and have eliminated that last burp. The whistle sound is annoying, but effective.

 

[Levitation]

I have babbled about this before.
The ONLY way to measure fuel in your boat and your airplane (and tractors, etc) is your watch. The engine run time on your display can be your watch.
Fill or put a measured amount in.
Know or estimate your fuel burn from your engine manual.
Keep a notebook at the helm for recording engine run time, estimated fuel burned, and estimated fuel remaining.
After your first season of doing this and comparing the amount of fuel it takes to refill it against your estimated fuel burn in the log, you will have it down to a science.
You will not run out of fuel. The seas will always be calm when you go out. And you will hit the lottery.


Well, 1 out of 3 ain't bad :mrgreen:

 

[rporterfield]

Steve
When possible it is best to fuel whenever you return to port and keep the tank as close to full as possible. One, to prevent water condensation, and two, to reduce the growth of organisms in the fuel. The rule is to start with a full tank, 1/3 to destination, 1/3 to return and 1/3 reserve. There are fuel additives for diesel fuel to prevent the grunge. I use Amzoil for my diesels to keep the injectors and fuel lines clean. They also have products like Cold Flow for those who have temps below forty degrees to prevent the perifin from forming and plugging the filters and injectors.

Robert

 

[b1itsjustme]

You are about to run out of fuel. I did! The gauge needs to be set up according to the two ways of doing it. One is to add 80 gals to the empty tank and mark it at 16 gal intervals, which failed, or the other which is a general way. Either way is just a guess as the fuel gauge will change with the angle of your running. When at rest it's somewhat close, but I'm not going to run it with less than 40 gals in it. Neither do I want to carry the extra weight of the full 80 unless on a trip. I do run my boat quite a bit, and not always at trawler speeds so I do go through the diesel.

Note, when you run out of fuel it will shut down instantly. No coughing or stumbling. One second on, next second off. Luckily I had the Volvo tech on board at the time to fix the overheat issue with the D3 220, and had SeaTow. The Volvo tech added fuel to the filter to prime, but I'm not sure it needed it. Hope I never have to find out as I now carry two fuel cans in the propane locker on the swim platform.

As for the overheat issue, you have to replace two hoses which collapse at high speed causing starvation of coolant. They are a stone bitch to get to unless you do what I eventually did, which is to rebuild the box in front of the engine bay in the lower berth area to be removable with just a few anchorage points. Why it is so hard to imagine you're going to need to get into the front of the engine bay? Duh!