where to start? Fuel gauges not working

[sluggo]

I have an 87 10 meter mid cabin twin 454 crusaders. The fuel guages worked last yr, I just figured I was real low. Well I got a fill up ( 200+ gals x $4.19 and no vasoline with that!!) guages did not move. Neither of them. I'd be surprised if they both went out at the same time, that's why I think it something else. When I turn the 'key' the needle jumps, but from the far left below 0 to o/o and that it is it. Any ideas as to where to start to chase this down.

[reelfishin]

I would check the ground on the fuel gauges. I imagine they have a common ground. It could be a bad connection there.

[P-Dogg]

American senders are about 230 ohms at low and 30 ohms at high (full). Disconnect the wires from the sender and measure the resistance. Make sure that you have a good ground as stated above. If you think that your tank is full, you should get near 30 ohms. Reconnect the wires, then disconnect the wires at the gauge. Measure the resistance on the wires where they attach to the gauge. It should be pretty darn close to the sender values. If both of those values are in agreement, suspect the gauge. If not, you have a bad connection between the two locations. If you have two gauges, switch wires between them and see if the problem remains.

Having re-read your post, another item comes to mind. Have you checked the power to the gauges? Loosen and then tighten all of the screw terminals serving them, and check for a blown in-line fuse (less likely, since the needles move when powered-up).

[prowlersfish]

You lost boat gages , at the same time . Each should have its own power source from its respected ignition switch so that should not be the problem but check it anyway for a full 12 volts +- , look at the grounds at the gage ( shared ) . But what I would suspect it the ground going to the full tank or tank senders as it maybe from a common source . look for broken wires at the negative battery area and at your ground buss bar (bus bar / bus bar)

Yes there are 3 different ways to spell it , at least when you go looking for one you will find it list 3 different ways depending on who makes them .


Now is it a gauge or a gage ?

[prowlersfish]

Well while where on the subject , Its time to see if my fgages still work . I will ad some $$$$ and see

[sluggo]

Thanks for the ideas guys. Before I did anything, I ran the boat, turned my back, and looked again the port one started to work!! Well at least I have 1 so I should have an idea how much fuel I have. ran the boat the next day, same thing, this time the starboard started working. As I ran the boat, I did see them registering less fuel (a real bummer for sure). Again thanks for the ideas, I'lll keep them handy just in case.

[yorklyn]

check the connections to the sending units on the top of the tanks. I have two round inspection ports directly above mine. it doesnt take much water to corrode the connections. the factory sending units are mechanical units with a plastic "disk" on top that is held in with two small screws. the disk is easlily damaged but is easy to replace.

[sehord]

You will ultimately find you have a bad ground. Check all grounds (read wiggle) while someone watched the gauges for activity

[koviak]

Yorklyn, do you know what type of sending units are on the tanks? I have one not working and its a bugger to access. Perhaps a picture of it, I have seen pictures of your deck with inspection plates. Did not want to do this unless no other choice. Thanks in advance.

[yorklyn]

Mine is made by moeller. If the sending unit itself is pretty hard to damage. The replaceable gauge/ sending unit on top is eaisly screwed up. I just put mine back in or I would take a picture for you. it looks like this but I believe ours are the 22 inch model
http://greatlakesskipper.com/en_us/moel ... nding-unit

Google moeller 22 inch mechanical gas sending unit.