Temperature Gauge Flashing

[Reelfun]

I have a 200 SWS that was recently rebuilt. The temperature gauge flashes all the time, even with the switch just turned on and the motor not running. It flashes when running also, but motor is not hot to the touch. Possible causes?
Thanks, reelfun

[Dennisg]

Hi, hopefully someone else will come forward with a more positive answer than this, but I will take a guess, and say what I would look for if I were in the same situation. I know that when the motor is hot, the sending unit grounds out electrictly, so I would look at the wireing for a possible chafe against the block, or a corrodded connector/plug type connector, where the corrosion has caused a short to ground. One thing more you could try, is to disconnect the sending unit form the harness, and see if the flashing stops, if it does, the sending unit is toast, replace it, and you should be good to go.
Dennis

[boats.net]

First check the warning buzzer is working properly. There is a pink and black wire going to temp sensor on top of each cylinder head, disconnect wires from sensor and touch them togather, turn ignition key on and buzzer should sound. If thats ok then look a wire connected wrong or not connected at all. You didn't say what year motor you have but on the older motors the temp light wire(gray wire) had to be connected togather on engine where the 2 4 prong connectors for oil/trim harness is, make the gray wire is pluged in between the 4 prong connectors and not touching metal to ground it out.

[Reelfun]

Thanks for the feedback. The year model is 1998. I took the wires off of both the sending units and touched them together and the buzzer works. I did not notice any loose wires anywhere. The firm that rebuilt my motor put a different type multi function gauge in than the one I had before. The original gauge and the new one are both Yamaha gauges. Could it be the wrong gauge or a different wiring pattern? Could the thermo sensor on the bottom of the left head cause this type of problem?

[jb123]

look at your harness connections at motor...ensure the SINGLE gray's are connected....one has a large clear sheath and USUALLY arent connected.