issue with fuel gauge

[bebeard]

Good Day All,

I hope you can help me. I have a 1977 Challenger Bass Boat with a Merc 1500 150 HP, and a Mercontrol Throttle Box.

My Ignition switch when out, and I replaced it with a new identical one, and performed a wire to wire swap out and soldered each connection.

Well, now I am having a problem, and I don't know where it has originated, but there is a primary accessories power to the batter that runs my gauges, lights, & trolling motor, but when I have the key out of the ignition switch, the fuel gauge shows "Fuel", but when I put the key in the ON or START position the gauge drops to "Empty". I cannot figure this out... can anyone help?

Please let me know if you have any other questions...

Thanks in advance,

P.S. Please feel free to email me directly if neccessary: e_beard@hotmail.com

Brook

[zooker]

hmm you put the wrong wire in the wrong place... my guess is the fuel gauge sender unit wire which should NOT be conneted to the ignition switch. only the fuel pump wire..which means the fuel pumps should come on when the switch is turned to the start /run postion..

zooker

[bebeard]

hello Zooker,

When I wired the ignition switch, I did a wire to wire change out with the exact same switch, and didn't make any changes..

The hot wire for the accessories including the gauge come straight from the battery.

Thanks again,

Brook

[zooker]

ok so it is the accessories hook up.. if it does this with the gas gauge it should do it with EVERYTHING..if not it's the gauge it self..

zooker

[bebeard]

well, from what I can tell, all my other gauges work... with my MPH gauge, can I check this by putting it in gear?

Otherwise, do you have any suggestions on where I should look? is there a way to determine if the gauge is bad?

Thanks so much!

Brook

[bebeard]

Ok...

it has finally been nice enough to get out and do some testing... but here is what I have found so far...

I disconnected all my hots from the battery and then just connected the accessories power supply, and all works fine. Even with the key in the ignition and in the ON or START Positions, the gauges work fine. The issue that I have found now, is that when I connect the "primary" power supply and then put the key in and in the ON or Start Position the fuel gauge drops to "Empty"..

Hope this helps, and thanks for the help!

Brook