Fuel Guage problems

[bigtom]

Just got our old 77 RegaL On the water yesterday. The baot had set for 8 years or so and the wiring was Very shooty and had to redo most of it. We pumped 40 galans of fuel out of it and put 20 back in. The fuel guage isnt reading anything, The sending unit in the tank tooks good when I had it out. I could stick a ohm meter on in and the resistance would change with moving the float. Does anyone have a good diagram or could explain How the guage is wired, including the sending unit in the tank. I done a search and caould have found some good Schematics but some of the links were not working.
Thanks

 

[Silvertip]

Re: Fuel Guage problems

First, if the gauge reads empty when you know the tank has fuel in it, the float on the sender may be heavy and no longer floats. Take it out and test it. The sender should measure 0 - 240 ohms as you move the arm. If those two items check out, install the sender. There are only two wires on the sender. Ground and the send wire. Make sure the ground wire is indeed grounded. The send wire goes to the send terminal on the gauge. You can again use your ohm meter to test continuity of that wire. Turn the key on. You should measure +12V on the "I" (Ignition) terminal. If not, you need to fix that. The gauge has a "G" terminal (ground). Make sure that terminal is indeed grounded. If not, fix it. If the gauge does not work at this point you either messed up your measurements or the gauge is shot. The gauge may have an "L" (light) terminal. That terminal should have +12V on it when the NAV lights are on. Some are on anytime the key is in the RUN position.

 

[bigtom]

Re: Fuel Guage problems

Good deal, I try that tommorow and see if I get anywhere. If not O guess Ill have to buy some parts. Thats what I was looking for.
Thanks

 

[Boatist]

Re: Fuel Guage problems

I have the same problem with my boat but I know my problem is internal to the guage. When the tank is full can just tap the guage and it breaks loose and works the rest of the day. When the tank is half full or less must hit the guage hard to break it loose. Problem has slowly been getting worse. If I find the time on July 4th I am going to take the cover off the guage and clean the stop post. if that not enough will lube with some teflon lube and see if that makes a difference. Must fix before our week long trip to the ocean as must know how much fuel have when off shore.

As stated above with the key on make sure you have 12 volts and a good ground and that the wire going to the sending unit changes voltage at the guage as the fuel slops around in the tank.

I let you know If I solve my sticking problem.

 

[Boatist]

Re: Fuel Guage problems

I was able to fix my fuel guage today. July 4 it was 105 in the shade and my boat is in the sun so did not even try.
Today got out the meter and got under the dash. With the key on the fuel guage does not move at all just stays on E. Had 12 volts to the power line and a good ground. Checked the sensor line and it read 2.5 volts. I hooked a jumper to the sensor terminal on the back of the guage and ground to the wire and the guage broke loose and read 1/4 full. When I turned the key off would stick again.
Turned the key off to kill all voltage to the guage. Removed power wire, ground wire, sensor wire and the light. Then I removed the guage. Took a while but figured out how to remove the front glass and the rear cover.

I found a lever I could rotate to change the tension and I turned it to where the guage with no power was below E but not againist the stop. ( big Mistake) When I hooked up the wire to test the guage went all the way past full to the other stop. So I turned it back but not really sure how much fuel in the tank. Finally I pulled the tank inspection plate and checked the mechincal guage. Found it set to just below 1/4 full. Adjusted the guage to read the same. Turned the key off and again the guage would stick on E. Took some alcohol and a Q tip the gently cleaned the stop post and the needle where it hits the post. Turned the key on and and it jumped to 1/4 full. Off and on and works perfect even after sitting in the off postion for 5 hours while I worked on our sprinkler system. So mine is now fixed.

I hope something here may be able to help you.
Good Luck