Do as I say not as I used to do!

T

trailertrawlerkismet

Well-known member
Joined
Feb 23, 2011
Messages
2,519
Fluid Motion Model
C-24 C
Vessel Name
(2022) Kismet
On the way from Roche Harbor to Anacortes my Garmin GPS showed I had 35 gallons of fuel. I've always added whatever number of gallons into the Garmin when I fueled up and I was certain I had 35 gallons when I left Roche Harbor. About 4 miles out of Cap Sante I slowed down to a slow pace and at 2 miles out, showing 25 gallons on the Garmin display the engine alarm went off and the engine quit running. My first thought was impeller but I had water discharge upon restart. Engine problem but the engine compartment was dry and the oil level proper. The engine did restart but the engine was only able to operate at idle. I continued into the marina, prepared the lines and fenders and once inside the harbor went directly to the first open slip. As I approached the slip the engine died again, all the while the engine alarm continued to blare....no overheating either. Long story short when Andrew suggested I check the Yanmar display, which I never have done, the fuel level showed zero!!!! Moral of the story is the Yanmar display is accurate and should be consulted. This story could have had a completely different end result, I got lucky but want others to learn from my embarrassing situation.

Jim F
 
Thanks for sharing.

I frequent an RV site that has a separate section for bloopers and "Do as I say" items.

No bashing allowed. Just a spot where one can share (and learn) what to do and not do.

may be something to consider for this site.
 
trailertrawlerkismet":3qtvubxd said:
On the way from Roche Harbor to Anacortes my Garmin GPS showed I had 35 gallons of fuel. I've always added whatever number of gallons into the Garmin when I fueled up and I was certain I had 35 gallons when I left Roche Harbor. About 4 miles out of Cap Sante I slowed down to a slow pace and at 2 miles out, showing 25 gallons on the Garmin display the engine alarm went off and the engine quit running. My first thought was impeller but I had water discharge upon restart. Engine problem but the engine compartment was dry and the oil level proper. The engine did restart but the engine was only able to operate at idle. I continued into the marina, prepared the lines and fenders and once inside the harbor went directly to the first open slip. As I approached the slip the engine died again, all the while the engine alarm continued to blare....no overheating either. Long story short when Andrew suggested I check the Yanmar display, which I never have done, the fuel level showed zero!!!! Moral of the story is the Yanmar display is accurate and should be consulted. This story could have had a completely different end result, I got lucky but want others to learn from my embarrassing situation.

Jim F
Click to expand...

I'm idly wondering if there is a connection between this post and the preceding thread. Just a thought...
 
I think this is worth revisiting to help the rest of us avoid the same fate. Checking the engine display to confirm the Garmin is correct does not address how you ended up with no fuel. I'm having hard time understanding how to end up with less fuel than what the Garmin indicated. The most likely scenario is to have more fuel than what the Garmin reads. I want to make sure I don't end up in the same situation thing some day.

There are several scenarios I can imagine that may result in a small difference between the two systems but very few that would result in such a large discrepancy.

Here are the scenarios I can think of (and worry about!)

1) Forget to reset the Garmin on refueling. I've done this so I know it is likely but it results in having more fuel than indicated, not less so it could not be this.

2) Enter the wrong amount for fuel added. Most likely. I typically hit the "fill up all tanks" button rather than the more complicated numeric entry. However, given the other options I think this is most likely what happened. It is possible the fuel burped in the line making you think it was full and then entering "fill up all tanks" incorrectly set the tank to full. Though it seems you would noticed the number of gallons added.

3) Regularly fill only nearly full. Unlikely to result in this much error. If you typically estimate when it is full and stop early to avoid overflow this will result in less than a full tank. If done repeatedly while using the "fill up all tanks" selection it could build up to a difference of 25 gallons over time. Now and then I take it to completely full risking a small spill to make sure this isn't happening.

4) Fuel flow sensor is bad. Unlikely, since you've had no other symptoms.

5) Garmin SW error or system lockup of some sort resulting in incorrect display reading. Also seems unlikely with no other issues reported.

6) Fuel tank leak. You would have noticed (and smelled) fuel in the bilge. Unlikely.

Can anyone else think of other possibilities? Is the incorrect entry the only likely scenario? Jim, any thoughts on which of these is most likely? From now on I plan to verify the two systems match on each fill up.
 
On my C30, the fuel used by the generator is not accounted for in the garmin reading. At full electrical load for me, this can be over 2 gallons per hour I believe. Here in Florida, this does make a difference.
 
A number of things can cause error on the Garmin calculated display. As noted, the Garmin is not aware of Genset or diesel heater/stove fuel use. The engine does not directly measure fuel flow, it is calculated based on fuel rail pressure and injector pulse duration. The rail pressure sensor has a tolerance, and the injectors also have a flow tolerance that could vary as they age and wear.
The worst case scenario is never filling the tank and always entering the amount of fuel put into the tank each time. Any small errors based on tolerances, genset use, or heater use will accumulate over time. even the fuel pump indication when you buy fuel has a tolerance, you may not be getting the exact amount it indicates.
If you always fill (or very nearly fill) the tank each time you add fuel, then use the Garmin Fill All Tanks function, you will be resetting each time. Even if you do not completely fill the tank, you will not accumulate error over time, but will have a slightly different error each time based on how full you fill the tank. If you always fill to 95 gallons and reset the Garmin to 100 (full tank for R27), you will always initially have a 5 gallon error. Each time you do this you will reset to a 5 gallon error.
I have been logging the Yanmar fuel gauge (which is based on the float sender) and the Garmin fuel remaining (calculated based on engine data) for some time now. I plotted these and see some interesting results. The Yanmar fuel gauge really likes certain values and steps between them. In my case I frequently see 100%, 88%, 74%, 63%, 56%, 50%, and 45%. I rarely see any other values. In general the Yanmar display is reasonable, at least down to 40 gallons or so, the lowest I have gone. I put the plot in my album:



Howard
 
I'm with you Red Raven. My Volvo gauge is off by 20 gallons . I rely on my Garmin, I have it set at 80 gallon capacity . Each time I fill up I log it and reset the Garmin. If I put 20 gallons in the tank I log it and reset Garmin and enter 20 Gallons. Each trip I log fuel use and hrs . This is my fuel gauge and on average I'm 1/2 gallon off+/-. My Volvo gauge reads 3/4 tank when I have 38 gallons in the tank. That is at idle, running level. I don't rely on the gauge at all. I hope that never happens to me !
 
Another scenario which has resulted in less fuel in the tank than indicated by the Garmin:

My C28 is kept on the hard mounted on pedestals. The pedestals situate the boat at a approximate 5-10 degree bow high attitude. The boat is set in this configuration after each use. I fuel the boat after each use while in this configuration until the tank is full as determined by fuel running from the vent and visible in the fill tube. The Garmin is then set to "full tank".

Recently, I fueled the boat at the marina while the boat was in the water (I presume level). According to the Garmin, it should require 62 gallons to fill. After pumping in 71 gallons the fuel began to foam from the fill tube but nothing came from the vent. A difference of 9 gallons, though not as drastic as previously reported, is still significant.

The only explanation I can wrap my thoughts around is that filling the tank while the boat is slightly inclined bow high results in a reduced amount of fuel the tank can accept; yet still indicates full.

What I failed to do was check the Volvo gauge while the boat was stationary and floating in the water. This may have supported or refuted my theory. The Volvo gauge always reads full while enroute due to the bow high attitude.

I believe many folks fuel while the boat is on the trailer - the same situation my exist while doing this...

Gary
 
I usually top off and hit the fill tank choice. If anything I forget to enter that I filled the tank, which means I would have more fuel than indicated. However, I occasionally will go to idle and compare volume on the Yanmar display to the Garmin amount to cross reference.
 
On our R31S we regularly fill our tank to full and reset the Garmin to FULL. We do not add gallons as this is prone to mathematical errors. Filling the tank to full is fairly fool proof and we are always within a gallon of the Garmin estimate. We also check the Volvo gauge at stand still against the Garmin. They corroborate the fuel supply. Underway, the Volvo gauge is subject to the tilt of the boat and sending unit from the tank and shows far more fuel than actual.
 
We use a fuel whistle on our fuel tanks vent line. I add fuel until the whistle stops whistling. I add the recommended amount of FPPF fuel additive. Then I use the fill all tanks option on the Garmin. I rarely run our boat on much less then 1/2 tank. When I fuel I always check to see what the Garmin says as far as gallons left and it seems to be pretty accurate when I add what fuel was added and come up pretty close to the 100 gallon mark. We have a generator and have not noticed that that is much of an impact on fuel usage as we don't use it all that much. We do occasionally run the generator for the A.C. while cruising if temps gets into the higher 80's or better. I think those who trailer a lot; want to end up at the end of a trip less than 50 gallons of fuel before putting the boat back on the trailer and dragging the extra weight.
 
In my case, the original poster, I have figured out my fuel problem. I was just getting back from a summer of boating when we used our generator a great deal. I never calculated or knew this fuel usage was not calibrated thru the Garmin, mistake number one. When I last fueled I only added 25 gallons as I knew I would be trailering Kismet in a few days for a cross country trip and did not want the added fuel. Not having topped off to be accurate and not allowing for the genset fuel usage contributed to running out of fuel. My lesson learned is to take genset fuel usage into consideration when adding less then a full tank of fuel.

Jim F
 
Jim,
A question I have had is how much fuel do you have left in the tank when the boat runs out of fuel ? When doing long runs without fuel availability we calculate how far we can go without running out of fuel . I am using the 10 percent figure. 80 gallons , 8gallons of unusable fuel. 10 present reserve ( need to get fuel at 65gallons used ). So Jim how much fuel did you have left in your tank when you filled up after running out of fuel ? I am assuming Ranger/ Cutwater use the same tank manufacture for all models so the pickup spacing should be the same at the bottom of the tank.
 
Thanks Jim, that explains it. I don't have a generator and thus had forgot that factor. We do have a Webasto heater and so will still need to check the level gauge now and then.
 
Just a thought. Since you ran the tank dry and maybe sucked up junk from the bottom of the tank, should you change the fuel filters? I'm asking because we use our generator alot and I'm sure it will happen to me at some point.

Tim
Gratitude
 
The fuel is always drawn from near the bottom of the tank regardless of the fuel level, the pickup is fixed. If any crud builds up to the height of the pickup it will get drawn into the filter, even with a full tank.
Now if there is something floating on top of the fuel and you run it dry this may get pulled into the filter.

The Mase IS 2.7 uses a little less than 1 Qt. per hour at full load. You could probably estimate a gallon every 5 hours or so.

Howard
 
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