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Manifold sending unit to controller

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shade2u2

New member
I have a 1984 M360 and need then sending unit that goes in the exit end of the riser and has a wire going to the controller.
Is this specific to this engine or will a generic temperature sending unit?
Where can I get one?
 
Generic will do it, but be sure to get a single helm or a double helm sender unit (depending on which you have). They are different!

Jeff
 
Do you have a gage at the helm for exhaust manifold temperature? If not and it is one wire and in series with the sending unit in the center head manifold, it could be a temperature switch, not a temperature sending unit. The temperature sending unit in the center head manifold, gives you your engine temperature reading. The temperature switch in the exhaust manifold when tripped will ground your sender and put your engine temperature gage to full hot position.
 
This Is my take on how a the temperature sending circuit works on my boat at least,which has dual stations and a single wire going from the temperature gage to thetemperature sending unit on the center head and then on to the exhaust manifoldtemperature switch.

If anyone sees a flawin my explanation please let me know.
Thebattery 12 VDC voltage goes to the engine temperature gage. From there it goesto the temperature sending unit on the intake manifold. This temperaturesending unit varies its resistance to ground in direct proportion with the actualcoolant temperature values at the thermostat location on the center head. 300 Ohms for 100 degrees and approximately 100Ohms for 200 degrees on some senders. The lower the resistance of the sender thehigher the voltage at the temperature gage. The temperature gage has a bimetallicstrip that deflects more with higher voltage. Therefore the higher the voltageat the temperature gage the higher the temperature reading is.
Inseries with the center head manifold temperature sender is the exhaust manifoldtemperature switch. This switch when tripped at around 210 degrees grounds thetemperature sending unit which deflects the engine temperature gage to full deflection of maximum heat display.
FastJeff is correct in that dual station sending units are different than singlestation units because two or one gauges have to be provided with the correct currentto ground.

Theexhaust manifold temperature switch does not care how many helm stations thereare because it is just an on or off switch.
 
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Here are some pictures of what the senders and switches look like. The D at the end of the part number for the sender is for a dual station set up and has 1/4" NPT. If yours is a single station you need a different sender. Your sender and switch NPT thread diameters need to be verified before you buy your parts.
 

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