curious fuel sender problem

[1015]

I just bought a 2000 Chris Craft 215 CC, Volvo 5.7 GS, SX-M drive. It has a few glitches, one of which is the fuel gauge always reads empty. It has power, the gauge moves from very empty to empty when ignition is turned on. After, reading numerous posts, I checked the fuel sending unit. I removed it, checked the ohms (it is in the 30-240ohms range), then reconnected it again outside the tank. When I articualted the arm several times, the gauge moved between 3/4 and 1/4 correspondingly (not great but something). I reinstalled the sender. The gauge still reads empty. Yes, the boat has gas, 3/4 of a tank. Any ideas?

The sending unit has three wires, a pink connected to the center post and a black and thick green wire plugged into a tab-style connection. I'm guessing pink-power, black-ground, but what is the green wire and why is it attached to the black wire?

 

[Gary H NC]

Re: curious fuel sender problem

Pink wire goes to the S terminal on the gauge....Black is ground for the sender and gauge.
The green wire may be another ground to the tank.

Try testing by running a ground wire from the Neg. post on the battery to the ground on the sending unit.
Also if you ground the pink wire at the sender it should peg the gauge to full..

 

[Silvertip]

Re: curious fuel sender problem

The green wire is a bonding (ground) wire for the tank itself. Takes care of static electricity. The black wire connects to the shell of the sender and must show continuity between the shell of the sender and the negative terminal of the battery. There is no +12 volt power feed to the sender. Although the sender resistance measures properly when operated manually, the float may be saturated and will not float so it always shows empty. Remove it and see if it floats on a small container of fuel. For heavens sake -- be careful and do this test outside.

 

[Bondo]

Re: curious fuel sender problem

black-ground, but what is the green wire and why is it attached to the black wire?

Ayuh,.. As noted by Silvertip,...
That's the Ground/ Bonding wires,...
Obviously, Niether of them have continuity with the motor block....But they Should....

 

[JustJason]

Re: curious fuel sender problem

The other thing to keep in mind is alot of those sending units are cut to fit. As in when the boat was made somebody had to measure the depth of the fuel tank and cut the sending unit to fit it. Its all possible that whoever did it, didn't do it right.