Temp sensors

[12bravo]

I have a 1999 Mercury 150 2 stroke with carbs. During power head rebuild we lost the temp sensor from the port side head. I remember that it had two wires, one I believe was grounded. The one on starboard side had only one wire. Could some one tell me why a difference and will a one wire sensor work on the port side? Also, is there a way to check the sensors?

 

[Dukedog]

port side is for a temp gauge... starboard is for temp alarm.. completely different even though they look a lot alike....

 

[12bravo]

Thanks, I do not have a temp gauge but I do have an extra one wire sensor like on starboard side. How about using on port side also for alarm on both sides?

 

[CharlieB]

While using two sensors may seem like a good idea, it may cause false alarms.

These sensors ground to cause the electrical flow path for the alarm to sound. Running two sensors the conbined flow may lower resistance and allow the alarm to sound falsely.

You won't know until you try it.

If you could Ohms test the sensor while heating and see how the Ohm change. If it is a simple On/Off you may be able to use them this way. But if the Ohms changes on a gradual slope then they may not works so well together.

 

[12bravo]

Thanks for the help.

 

[Dukedog]

Thanks, I do not have a temp gauge but I do have an extra one wire sensor like on starboard side. How about using on port side also for alarm on both sides?

both with a "specific" purpose and will only work that way.. port is for gauge only, reads resistance constantly for a gauge, reason for extra wire.. starboard is a "switch", either open or closed, no in between, over temp only...tan/blue goes to alarm buzzer only.. tan to gauge only... yes you can use an over temp sensor like tha one in tha starboard head on both heads as long as you term all tan/blues under same screw on plastic block....

 

[12bravo]

Thanks for the replies. I have both sensors connected to the wire for the alarm buzzer.