Almost couldn't watch this guy after a while ................. you just KNEW what was going to happen. Laughed myself silly. He looked so believable you almost felt sorry for him.
Still laughing every time I think about it.
Floating Ground?
- Thread starter Gunni
- Start date
Still laughing every time I think about it.
Yes, the gauge has an "I" pole which connects to the ignition switch, so the gauge is powered when the engine low voltage circuit is on.
OK, so most likely you do not need the ground connection, assuming the tank is not grounded.
Precision instrumentation would use differential input, however it is unlikely your fuel gauge was designed for high precision. Most likely the ground terminal and the battery ground are wired together, so you should not need the ground connection going to the tank (again assuming the tank is grounded)
Guys,
The WEMA/KUS senders DC circuit is simply isolated from the tank & tank flange unlike the cheapo units.. It just means the WEMA/KUS/Moeller reed style senders don't use any part of the tank as a path for the sending units DC circuit.
If you put a DVM across the black or white or pink wire and the flange you will see no continuity. Unfortunately WEMA/KUS keep calling the negative side of the circuit "ground" when it is simply the negative side/path of the DC circuit between the gauge and sender.
*WEMA/KUS instructions are bas ackwards. By industry standards "PINK" is the fuel gauge "S" terminal and black or yellow is the negative. With a WEMA or Moeller reed type sender it does not matter which way you hook up the pink & black, it works the same either way. It is best to follow industry standards so the next guy who comes along does not do a "WTF"....?
The WEMA/KUS senders DC circuit is simply isolated from the tank & tank flange unlike the cheapo units.. It just means the WEMA/KUS/Moeller reed style senders don't use any part of the tank as a path for the sending units DC circuit.
If you put a DVM across the black or white or pink wire and the flange you will see no continuity. Unfortunately WEMA/KUS keep calling the negative side of the circuit "ground" when it is simply the negative side/path of the DC circuit between the gauge and sender.
- The tank should be grounded to ships ground with a green or green with yellow stripe.
- The *black wire of the sender should be connected directly to the gauge clusters negative bus (usually black wires but on newer boats this could be yellow.)
- The white wire, if using a Moeller reed style, goes to the "S" terminal of the fuel gauge.
- The *pink wire of a WEMA should go to the "S" terminal of the fuel gauge.
- Do not connect the black sender wire to the tank or flange instead connect it directly to the engine gauge panels DC neg bus...
*WEMA/KUS instructions are bas ackwards. By industry standards "PINK" is the fuel gauge "S" terminal and black or yellow is the negative. With a WEMA or Moeller reed type sender it does not matter which way you hook up the pink & black, it works the same either way. It is best to follow industry standards so the next guy who comes along does not do a "WTF"....?
Thanks Maine Sail, that makes sense. It is like electrical instructions are written in another language (and a number of the letters are Cyrillic). I am now comfortable that will not 1) blow anything up, and 2)have a high likelihood of success!
Gotta say, that KUS / WEMA sender looks like a nice piece of SS kit, no wires dangling in the tank.
Gotta say, that KUS / WEMA sender looks like a nice piece of SS kit, no wires dangling in the tank.
FWIW, our diesel tank has a "ground" wire from the metal deck fitting to the tank ground tab, and then a ground wire to the Neg. bus strip.
So Gunni I am very interested in hearing the results of your install as well as the model wema gauge you purchased. Also, why a Faria gauge and not a WEMA. As mentioned in previous thread mine is not working and wish to replace (always reads full). I checked my wires and have a three wire connection at back of guage and two wires at tank....
Were you able to use existing wires?
This weekend I am going to use tester and label wires on current sender and guage to get myself started.
Thanks!
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Install is on hold until I draw down my tank enough to safely pull the sender unit. But I feel confident that this will work well. Appears that KUS has acquired WEMA, but the sender unit remains unchanged. You just pick the model that matches your tank sender location (threaded or flange plate) , has the proper length and wire lead. In my case the two wire pigtail.
This is the American ohm range 240-30 Ohm and it has to be matched with a similar range gauge. I chose Faria because they look cool and the price was right (less than $30). I like that it has screw stud attachments and has a lifetime warranty.
This is the American ohm range 240-30 Ohm and it has to be matched with a similar range gauge. I chose Faria because they look cool and the price was right (less than $30). I like that it has screw stud attachments and has a lifetime warranty.
Before installing, Gunni, take a reading with the float at the top and at the bottom. This is will give you a metric in the event something changes years from now. You can check and compare and see if the float's resistance has changed. Keep that info with the manual so the next owner will have it available.
Brilliant, thanks Brian. 33 at the top, 241 at the bottom. KUS specifies that the sender provide 1" clearance to the bottom of the tank so when the gauge shows empty I still have a 1" fuel reserve.
So did you ever get the install done? This will be a winter project for me..... really miss not having a guage. Right now just using the log hour method....
If you know your probe length, you can calculate the number of micro switches in the 0-100% range.
This will give you the range of gallons in your tank, per micro switch or the accuracy.
I had a near empty tank, had a friendly fuel dock attendant slowly fill tank. Mine is 50 gallons.
1) I put in 2 gallons of diesel and Stopped
2) Waited for 3-4 minutes to stabilize gauge.
3) Wrote down the rough gauge reading and gallons added.
Rinse and Repeat till tank full.
I then produced a calibration curve. My probe length/gauge is good to ±5 gallons or 10%.
Why do I do this?
I estimate fuel use by engine hours. Expect to fill, say 10 gallons[by gauge and estimate]. Tell the fuel attendant give me 8 gallons. Wait and then top it off slowly.
Last time I said 25 gallons and it topped off at 28.
Thus I verify my sensor is working and make it reliable each time I fill up.
I think a working fuel gauge is a Boat Safety Device.
Jim...
PS: I also keep an extra 5 gallons in a yellow can aboard, or my gauge accuracy.
Fully agree about the essentials of a working gauge and am really feeling vulnerable right now not knowing. I have been monitoring hour meter and keeping a chart but this engine is new to me so I dont know for certain my burn rates. I am being generous with the amount I am using so I don't run out but would be nice to actually know. I am getting ready for a little trip and put in 25 gallons and will carry a 5 gallon can. Probably will open up and inspect level just for peace of mind. Does anybody ever install a bit of redundancy and add a sight glass (plastic) or moeller manual fuel tank guage #MOE 03575510. Had one on my 30 year old boat and it worked flawlessly.
NYSail,,, my 84 H27 has the original moeller mechanical fuel gauge. Still working well. The scale from F to 1/2 to E only uses half of the round gauge display, so it helps to have good light and eyesight to read it. When it is half way between 1/2 and E, I start looking for a place to fill up. Its only a 12 gallon tank, so not sure how well they would work in a larger tank.