Fuel Sender hassles – end in sight?

[Steve W10]

Has anyone had any experience with the US Marine
"Fluid-trac 2 Wire Level Sensor (Resistive Emulation)" sending unit? (no moving parts)
See attached PDF.

Richard at US Marine confirmed....

• It can be used with diesel, black water, or fresh water.
  It is programmed at the factory for depth only; they stock units programmed for various depths, but don't seem to custom program for shape unless there is a min order of 100 senders.
  It will work with my existing Teleflex gauge or any gauge that reads 33-240ohm, which seems to be the industry standard here in N America.
  It is a direct replacement for our original senders, however a focus tube is sometimes required if the angle of the sender to the fluid is greater than 5%.
  Mounting the unit 3 inches from the edge of a 12 inch deep aluminum diesel tank will work but a focus tube is always a good idea as it only reads what is in the tube.

So, I suspect the vast majority of us have dealt with Teleflex a few times and maybe other companies and have resigned ourselves to measuring fuel by hours rather than with the gauge.

I've ended up dipping my tank at the end of each year and carrying a jerry can of diesel all the time but have now had enough of that.

If no one has any experience with this unit or even a similar one, I'll be the guinea pig and pick one up for launch in spring.  I will report back.

[Ron Hill]

Steve : There is NO fuel gage that will ever be accurate in an asymmetrical fuel tank!!

Our C34 fuel tank is wider at the top than at the bottom, wider at the front than at the rear.  There is no way that a simple float can register fuel capacity accurately by electrical resistance from symmetrical wire windings.  It would have to be on a logarithmic type scale.  
At the present time, when the float is half way down you have used about 2/3ths of the total capacity of the tank!!!  That's NOT - 12.5 gallons.  (My tank is stamped - 25 gal capacity)

Just use about .5 gal per hour to calculate fuel consumption for the M25XP engine!!  

[Ken Juul]

My boat is heavy....I'm averaging 0.6 gals/hour with a M25XP.  I'm tempting fate, but my sender is original as far as I can tell and is still working.  Half tank is about 9 gallons, 1/4 tank is between 14-17 gals.  Empty is empty....no fuel  warning light.  I have 5 gallons on the bow...had to use it once.  Otherwise try to fill before the 1/4 mark.

[Indian Falls]

My original sender wore out.  It was loose so that the wiper lost contact with the resistor part.  Being cheap and capable of repairing most things .. I pinched the housing in a vise to remove the slop in the axel that the float rides on.  Of course it was too tight and the cork bouyancy in diesel did not overcome the resistance I added by crushing the thing in a vise.  I drilled out one of the rivets and used a cotter pin in the rivet hole that allowed me to set the preload on the axel by bending the pin legs a bit wider and wider until the tension was right. "Works fine lasts a long time". Most folks would never see this being worth the time when you can just order another sender... But that's just me.  Its good practice for being at sea, right?. 

[Steve W10]

Reporting back....
Wow, I drafted this two years ago and apparently neglected to post.  Sorry guys, added a few points, and here it is....

Short Answer..... Fabulous!

First, Dan I love your repair, always a good feeling, congrats.  Mine just keep failing and really didn't work from the start.  When I tested brand new units at the store, resistance went from 80 to infinity at about the 2/3 mark.  I tested every one there and they all did the same thing.  I think Teleflex is just crap.

This is the one I bought....
http://usmarineproducts.com/osc/product_info.php?manufacturers_id=18&products_id=298
Part number looks to be.... F-D-110I-XX-2R-S-P4-012I-00000

Before installation I did run a few tests on the unit, but without getting into it too much, it was challenging and didn't provide any useful information.

The connector they had attached is pretty unique so I just cut and crimped on my own spades.  I just made sure to use plastic-protected spade connectors for the blue wire from the boat (hot); less important for the ground wire.

Although Rob at US Marine Products sent along a focus tube, normally $25, I decided to try it without first so I could let you guys know if it is required or not.....
Two years later - I have had no problems at all going without the focus tube.

Installed it on the boat and once power was applied it jumped to empty and less than a second later provided me what I think was a pretty accurate level.  Added 15 litres and it went up appropriately.

Took it sailing and........

So far I'm tickled, but time will tell.
Two seasons now and still awesome.  If anything changes I'll add to this thread, if you don't see anything, I'm still smiling! :)
I'll make an effort to get my tank near empty this season and let you know if how that works out.

I was never looking for a gauge that was spot on, who cares, I just want a ballpark without having to refer to my notes anytime I'm curious.

As an aside, contrary to popular belief, there are units that can account for unusually shaped tanks, some you program yourself, others like this unit, the company can do for you (once you provide dimensions), but these guys needed a run of 100 units to do that.
Honestly though, even talking about that difference in readings is a waste of time in my opinion; just know the bottom is smaller, no big deal.

Nice to have a gauge that works.

Steve

:) And please, of course I mean this in the kindest of ways, before you hit reply and retell that old one about ½ a gallon every hour, we all know that, this is for people that just don't like having crap that doesn't work. :)

[Noah]

I just went through the bad "jumping fuel gauge" game last month. A bunch of troubleshooting, new connections, ground wire replacement, etc. -- turned out it WAS a bad float sender. Problem solved replacing it with an off the shelf float unit from West Marine: $39.00.

[Steve W10]

Yeah, they can be had for less money for sure.  But after 2 failures in as many years, and even though Teleflex eventually provided replacements, I had enough.  This no-moving-parts emulator is truly what I was looking for.

Glad you got it working Noah.

Steve

[Noah]

I am like you...understand the limitations of the non-square tank for accuracy or lack of... just hated seeing fuel gauge jumping around...screaming "I'm broken". I could have hooked fuel tank up to my SCAD water and waste tank monitor which will read 8 tanks (using a different fuel sender). The SCAD  can also allegedly be calibrated for the "triangular shaped"  tank however, that would have left the cockpit gauge "abandoned" and my tank monitor gauge readout is at the chartable and not ideally located for my eyes. But it does have a level alarm so maybe I will try that set up "another day."

[mainesail]

I just went through the bad "jumping fuel gauge" game last month. A bunch of troubleshooting, new connections, ground wire replacement, etc. -- turned out it WAS a bad float sender. Problem solved replacing it with an off the shelf float unit from West Marine: $39.00.

The cheap Teleflex/Moeller senders are horribly unreliable. The WEMA senders and the mechanical with sender capsule are nearly bullet proof. Personally I use the mechanical with sender and have been for well in excess of 20+ years. The only time I saw one get flaky was when the fuel was so dirty it was plugging a 30 micron filter in 2 hours flat. The sender had so much gum & tar on it that it looked like Bob Marley's  lungs... Hardly the fault of the fuel sender.

Testing A Fuel Sender
http://www.pbase.com/mainecruising/fuel_sender_testing

As for calibration to your tank, it's called a "deviation card" just like the one every sailor is SUPPOSED to have on-board for the compass, but the vast majority don't........ 

#1 Empty Tank
#2 Know factory stated capacity of tank
#3 Fill tank in one gallon increments and note Empty, 1/4, 1/3, 1/2, 3/4, 2/3 & Full on the deviation card...
#4 Stop filling when it gurgles and is about to spit. This is your installed capacity and it very often varies from the stated capacity.
#5 Done......

[Steve W10]

Good info Mainesail.

Not saying the emulator is best, merely wanted to share information that I have not found anywhere before.
I'm still very happy with my choice, as I recall the WEMA stuff is almost as expensive as the emulator? and I'll still take zero moving parts over one moving part.

Although I really couldn't care about the exact deviation in a practical sense, curiosity got me and I actually created a spreadsheet that would do the math for me based on the shape of the tank.  Back then with useless senders I was dipping my tank at the end of the season, and re-checking after I added fuel.  If I recall, my math was pretty good.  But that of course does not take into account any inherent errors of a functioning sender; your method would be much better for that.

Again, I'll try to get some more info if I can get the tank down near empty.

Also, please, if anyone has any negative experiences, please pipe up, a review of one may not be all the useful.

Steve

[Indian Falls]

I just can't resist chiming in on this one... my fuel sender hack is working fine, lasting a long time.