Water Temp Sensor Question - 78 Ski Tique

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   When I turn the ignition to the first position, all my gauge indicators (except speedo & tach) jump a little, except the water temp. So my water temp gauge is not working. I did the following:

1.) Disconnected sensor wire and shorted sensor to ground - got the indicator spike - gauge is good.

2.) Bought and installed new sensor - turned key and no little jump so I hooked up the hose, fired it up, keep my hand on the exhaust manifold and watched the gauge - my hand got warm but the indicator did not move.

3.) Cleaned all connections, checked continuity on all wires - every thing clean and continuity checks out - still nothing.

4.) Pulled sensor, grounded it to the block and put a lighter to it - hey! the indicator starts moving.

So I examine the sensor hole and see it is coated with what I think is anti-seize, thus preventing a good ground to the block.

Got out the dental pick and cleaned up the threads, reinstalled sensor and turned the key - a barely perceptable indicator jump, turned key again and the jump is even less...etc.

My question are: do I just go with a mechanical vs an electronic gauge? do I use a big brass ring terminal and ground the exposed portion of the sensor to the block? and/or how the heck do I clean these threads?

My next post will ask about possible impeller failure noises.

Thanks

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
69 Mustang Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: April-26-2006 Location: United States Status: Offline Points: 402	Post Options Post Reply Quote 69 Mustang Report Post Thanks(0) Quote Reply Topic: Water Temp Sensor Question - 78 Ski Tique Posted: August-05-2006 at 10:09pm
	When I turn the ignition to the first position, all my gauge indicators (except speedo & tach) jump a little, except the water temp. So my water temp gauge is not working. I did the following: 1.) Disconnected sensor wire and shorted sensor to ground - got the indicator spike - gauge is good. 2.) Bought and installed new sensor - turned key and no little jump so I hooked up the hose, fired it up, keep my hand on the exhaust manifold and watched the gauge - my hand got warm but the indicator did not move. 3.) Cleaned all connections, checked continuity on all wires - every thing clean and continuity checks out - still nothing. 4.) Pulled sensor, grounded it to the block and put a lighter to it - hey! the indicator starts moving. So I examine the sensor hole and see it is coated with what I think is anti-seize, thus preventing a good ground to the block. Got out the dental pick and cleaned up the threads, reinstalled sensor and turned the key - a barely perceptable indicator jump, turned key again and the jump is even less...etc. My question are: do I just go with a mechanical vs an electronic gauge? do I use a big brass ring terminal and ground the exposed portion of the sensor to the block? and/or how the heck do I clean these threads? My next post will ask about possible impeller failure noises. Thanks
	For every complex problem, there is a solution that is simple, neat, and wrong. "Where the **** are we?" Amelia Earhart. July 2, 1937

Tim D Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: August-23-2004 Location: United States Status: Offline Points: 2635	Post Options Post Reply Quote Tim D Report Post Thanks(0) Quote Reply Posted: August-05-2006 at 10:40pm
	Mine doesn't do anything if it is cold; starting it for the first time. But after running it, switch it off, then later on switch it back on and it will jump to current temp. What temp does your gauge start with?
	Tim D

69 Mustang Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: April-26-2006 Location: United States Status: Offline Points: 402	Post Options Post Reply Quote 69 Mustang Report Post Thanks(0) Quote Reply Posted: August-05-2006 at 10:46pm
	Hi Tim First reading on gauge is 100. I just bought the boat last week. I put it in the water last Wed for the first time and idled it at the dock for 30 minutes - the gauge never moved. Because of this, I am not comfortable running the boat until I get this fixed. Thanks
	For every complex problem, there is a solution that is simple, neat, and wrong. "Where the **** are we?" Amelia Earhart. July 2, 1937

Tim D Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: August-23-2004 Location: United States Status: Offline Points: 2635	Post Options Post Reply Quote Tim D Report Post Thanks(0) Quote Reply Posted: August-05-2006 at 11:16pm
	In thirty minutes, it should be somewhere between 140 and 160.
	Tim D

69 Mustang Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: April-26-2006 Location: United States Status: Offline Points: 402	Post Options Post Reply Quote 69 Mustang Report Post Thanks(0) Quote Reply Posted: August-05-2006 at 11:26pm
	That is what I thought as well. Should I just go mechanical or the ground option? Thanks
	For every complex problem, there is a solution that is simple, neat, and wrong. "Where the **** are we?" Amelia Earhart. July 2, 1937

Tim D Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: August-23-2004 Location: United States Status: Offline Points: 2635	Post Options Post Reply Quote Tim D Report Post Thanks(0) Quote Reply Posted: August-05-2006 at 11:33pm
	Is there one wire going to the sending unit?
	Tim D

69 Mustang Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: April-26-2006 Location: United States Status: Offline Points: 402	Post Options Post Reply Quote 69 Mustang Report Post Thanks(0) Quote Reply Posted: August-06-2006 at 12:14am
	Yes, the tan one that connects to the "S" post on the gauge
	For every complex problem, there is a solution that is simple, neat, and wrong. "Where the **** are we?" Amelia Earhart. July 2, 1937

rmcdonald Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: December-30-2005 Location: Australia Status: Offline Points: 71	Post Options Post Reply Quote rmcdonald Report Post Thanks(0) Quote Reply Posted: August-06-2006 at 10:28am
	Hi Mike You said that you just got the boat. Do you know if the sender that you purchased is the exact match for you gauge Also that the sender unit is not a switch unit? A switch unit will only give a response if you go over temperature. Like putting a lighter under it. Switches are used with lights as opposed to senders which change resistance over a range of temperatures If the sender is not matched to the gauge it will give you incorrect readings. To test combination that you have you also can do the following. I took my gauge and sender out to do this but you could also do it with a bucket of boiling water in the boat. Get a � inch block of polystyrene foam and push the sender unit through the foam so that the bottom of the sender unit protrudes. Wrap a wire around the bottom of the sender unit. Connect the other end of this wire to the negative of you battery. Connect a wire to the top of your sender unit, Connect the other end to the correct position on your gauge. Connect positive12 volts to the + on the gauge. Connect negative to the ground position on the gauge. Place the sender in the foam in a Pot of water on the stove and turn the stove on. The sender will float with the bottom of the sender in the water and the top of the sender above. Put a thermometer in the water. You need a thermometer capable of reading over 220 degrees F Compare the readings from the Thermometer to the gauge. Check that the readings are correct between normal operating temperature and boiling point ( 212 degrees F) If the thermometer and the gauge match, you only have a wiring problem. I was unlucky I could not get a sender to match my 1960�s Stewart Warner gauge I had to buy a new Gauge. Regards Rob

69 Mustang Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: April-26-2006 Location: United States Status: Offline Points: 402	Post Options Post Reply Quote 69 Mustang Report Post Thanks(0) Quote Reply Posted: August-06-2006 at 12:51pm
	Wow, that sounds like a much more accurate way to test. Going to print this for the boat knowledge file. The sender should be a match based on a conversation with Teleflex. I think I'm just going to use an exterior ground.
	For every complex problem, there is a solution that is simple, neat, and wrong. "Where the **** are we?" Amelia Earhart. July 2, 1937

Water Temp Sensor Question - 78 Ski Tique

About CCF

Donate

Partners

Contact