I have a 2004 Skeeter with a Yamaha 150 outboard motor. When I turn the key to power the ignition, the fuel needle pegs to full. I can see through the tank that I only have a half tank of gas. I disconnected the negative lead on the sender and the gauge dropped to empty, so I think that the gauge is good. By the way, the sender is new. I'm thinking that it's a short somewhere in either the pink sending wire or the ground. Any suggestions would be appreciated. Thanks.
You can either measure resistance of sender or run a test wire of the same thickness as the sender wire to tank from gauge on sender post and see if issue remains.
Resistance test is easier and safer.
From briefly checking, US Marine fuel tank senders operate within 240 to 30 ohms. 240 is empty, 30 ohms or less would be pegged/full.
Turn power off, remove the sender, cover the hole to keep fumes to minimum so you don't cause a fuel explosion. Then turn power on and move sender arm away from gas tank hole.
If sender wire is correctly installed and not grounding against sender or tank if metal, but stays pegged when adjusting sender arm level, it would likely be bad sender.
