Gauges Stopped Working Abruptly On the Water

[wingtime]

WEMA all the way.   They are less pron to sloshing errors since the WEMA does not have a float arm.  Also since the Moeller has a float arm the reading you get is not perfectly linear since the arm travels in an arc.

[Bergertime]

I attempted to pull my sending unit out last night and 2 of the five screws are stuck.  Going to try some PB Blaster but I fear I may have to drill them out to remove the old unit and measure the tank.   I have a question though..

In looking my wiring I have two wires hooked to the existing unit which looks like a Moeller from the top.  One wire (looks pink) is bolted down to the center of the unit by a nut.  The second, RED is fitted to the male prong on the side of the unit.  I have a black and black-green wire that are loose.  When I disconnect the RED wire the gauge goes dead, connected reads half of tank.

From my research the Pink goes to the back of the Gauge providing the read from the unit but I am unsure what the Red one is for since the diagram from Moeller shows this to be a ground wire.  Does the stock unit in the 245 need 12V power?    Is the RED wire misplaced or hooked wrong?  Sorry for the dumb question but this electrical stuff still kinda puzzles me.

Moeller Diagram:
http://www.moellermarine.com/aftermarket/frequentlyaskedquestions/sendingunitsampgagesfaq039s/

Link to picture on my 245:
http://s1309.photobucket.com/albums/s634/Bergertime/?action=view&current=2CB8A193-A9F4-4E8C-90C7-198BD8875DF6-1908-00000181D7B69F2A_zpsf2fbcbec.jpg&evt=user_media_share

[flounderpounder225]

I attempted to pull my sending unit out last night and 2 of the five screws are stuck.  Going to try some PB Blaster but I fear I may have to drill them out to remove the old unit and measure the tank.   I have a question though..

In looking my wiring I have two wires hooked to the existing unit which looks like a Moeller from the top.  One wire (looks pink) is bolted down to the center of the unit by a nut.  The second, RED is fitted to the male prong on the side of the unit.  I have a black and black-green wire that are loose.  When I disconnect the RED wire the gauge goes dead, connected reads half of tank.

From my research the Pink goes to the back of the Gauge providing the read from the unit but I am unsure what the Red one is for since the diagram from Moeller shows this to be a ground wire.  Does the stock unit in the 245 need 12V power?    Is the RED wire misplaced or hooked wrong?  Sorry for the dumb question but this electrical stuff still kinda puzzles me.

Moeller Diagram:
http://www.moellermarine.com/aftermarket/frequentlyaskedquestions/sendingunitsampgagesfaq039s/


Link to picture on my 245:
http://s1309.photobucket.com/albums/s634/Bergertime/?action=view&current=2CB8A193-A9F4-4E8C-90C7-198BD8875DF6-1908-00000181D7B69F2A_zpsf2fbcbec.jpg&evt=user_media_share

First, be careful, touching wires down there around the gas tank.  My friend had a Boom... once doing that.  You should turn off your batts prior to connecting or re-connecting the wires.  The pink wire does come from the "Ground side" of the gage.  It is basically seekinig a ground through the sending unit.  The red wire you see is nothing more than going to the boats ground (-) system attached to the neg(-) side of the sender.  when you are removing the red wire you are removing the ground that the gage is seeking, that is why the gage goes dead.  It sounds like the sender is working correctly.

[Bergertime]

Marc,

The problem is that the fuel gauge never reads above a half of a tank even when the tank filled to capacity.  That said, do you think the sender is bad as some have mentioned?  I will get an Ohm meter and see.. especially since getting the unit out will be more problematic due to two locked screws.

[Capt. Bob]

While the gauge itself could be defective, the higher area of suspicion will lie with the sender. It (sender) lives in a much more hostile environment than the gauge itself and the function of the variable resister becomes degraded over time living with the caustic conditions found in the fuel tank itself.

[seabob4]

Berger,
Here's how the sender and gauge SHOULD be wired.  Coming off the sender should be white and black wires.  White, which is the "sender" wire, should be butt spliced to the pink wire in your boat's main harness, this wire in turn terminates to the "S" terminal post on the fuel gauge.  The black is ground, this can be terminated to a ground bus, either the one behind the access door starboard side aft, or the one inside the console.  The fuel gauge recieves it's ground daisy-chained off the tach or neighboring gauge.  There should also be a green wire terminated to the fuel tank or sender as well (I believe their was a bonding tab on the 245's tank), as your tank is aluminum, therefore it needs to be bonded to the ground circuit.  That green wire should travel up the fuel fill hose to the fuel fill deck plate, where it bonds the fill as well.

The red wire?  That sounds like a little suspect "work" was done by the PO...

[flounderpounder225]

the red sounds like the PO ran his own ground to an unknown location, using what color wire he had available, although it sounds like it is going to ground because of the gage reaction when disconnected.

[seabob4]

I think CB added a pic to my post...thank you sir!

Agreed with you Marc.  But at least the green bonding wire is there, spliced together with a ground...

[flounderpounder225]

Marc,

The problem is that the fuel gauge never reads above a half of a tank even when the tank filled to capacity.  That said, do you think the sender is bad as some have mentioned?  I will get an Ohm meter and see.. especially since getting the unit out will be more problematic due to two locked screws.

Definitely sender, as Bob stated, the "wiper" that changes the Ohmic ground value returned to the gage sounds like it has an "open" or the float arm itself is only moving half way up because of some restriction, either way the sender is going to have to be removed.  Use a quality #2 phillips screwdriver, and do your best, if they break, deal with it later, if the head strips, take a carbide tip drill bit about 2/3 the size of the pan head screw, start drilling slowly using a little oil for lube, you will drill the head off the screw and just leave the shaft of the screw in the tank (same as breaking the head off).  You can always come back later in between the damaged fasteners and install nut-serts, more later on screw repair

[Capt. Bob]

I think CB added a pic to my post...thank you sir!

Agreed with you Marc.  But at least the green bonding wire is there, spliced together with a ground...

My pleasure and done to bring your point home.
Repaired the member's link to that pic and the Moeller diagram.

I re-read his post and it appears to me that there is the possibly (in my mind anyway) that the black and green wires are not connected to anything.
Really need BT to confirm.

[seabob4]

I think CB added a pic to my post...thank you sir!

Agreed with you Marc.  But at least the green bonding wire is there, spliced together with a ground...

My pleasure and done to bring your point home.
Repaired the member's link to that pic and the Moeller diagram.

I re-read his post and it appears to me that there is the possibly (in my mind anyway) that the black and green wires are not connected to anything.
Really need BT to confirm.

That is entirely possible at this juncture, CB.  Originally, the black and green separated as they followed the fuel fill hose, the black heading either fore or aft (can't remember) to a ground bus, the green on up to the fuel fill...

[Capt. Bob]

That is entirely possible at this juncture, CB.  Originally, the black and green separated as they followed the fuel fill hose, the black heading either fore or aft (can't remember) to a ground bus, the green on up to the fuel fill...

That's the way mine was. It had two green bonds and one black (on the tank ground lug). One green to the fill, another to my brass ball valve at the raw water pick up and the black to the ground buss at the helm.

When I installed the new tank I ran 3 green (stupid anal). One to the fill, one to the existing gauge ground and one to the neg. batt. terminal.
I replaced the brass valve with Marlon so no green on the sea cock. The sender ground (black) went to the buss also.

[Bergertime]

Hello All..

The pic I provided is a little unclear as it kinda looks like they are attached but both wires joined by a clip are not connected to anything and were like that when I started digging around down there.    Based on the conversation I am surmising that the fill line and the tank are not grounded which is a hazard.  Can I connect both to the grounding buss in the back to remediate the problem?  To set up properly I think I need:

Tank Ground    
                        -----> Ground Buss
Fill line Ground  /

Do I need multiple grounding locations, i.e Ground Buss and other?

-Bruce

[Blue Agave]

Ground is ground.

[Capt. Bob]

Do I need multiple grounding locations, i.e Ground Buss and other?

Bruce,
As BA stated, a ground by any other name is still a ground.

Your tank is metallic, so is your fill. The proper ground to both is (hopefully) to prevent "KaBooms".
They can both terminate at your helm buss. The real importance is that the ground(s) are properly made and maintained.

Good luck.