water temp sending unit

[ajg6989]

Is the water temp sending unit on the deuce ground or postive Mine is not reading on the gauge now.

 

[cranetruck]

It's a temperature sensitive resistor, which is grounded to the engine. It measures about 4,500 ohms at room temp and decreases as temp increases.

 

[Alexander]

Can anyone tell me if the oil pressure gauge works the same way? My gauge (I hope not the pump) is very erratic. I think it's the 0-60 unit.

 

[SixBuy]

According to tha magnificent wiring diagram Peter Bog did, the oil pressure gauge works the same way; i.e. the sending unit is grounded and the gauge is hot. In fact , all four gauges have a common 24 V feed point - something to remember when things don't work right! I can't speak to the resistance of sending unit.

 

[Alexander]

Is the duce wiring diagram mentioned posted anywhere?

 

[SixBuy]

Peter Bog did an AutoCad redraw of the diagram that appears in the paper TM. He did a magnificent job and there was talk of posting it in another thread. You may want to do a search of the last few months and see if/where it was posted. I assume his intent was to distribute it freely so if you don't find anything PM me and I'll see what I can do.

 

[JasonS]

This is from the reo oa331 engine and clutch overhaul manual:

"Using constant current control, set at 26.8 each (??? mA), voltmeter reading must be 18.4 to 19.6V with unit in water at 200f having minimum flow of 10fpm past the unit and with power on form a minimum of 6 minutes." Not easily duplicated by the DIYfer. Assuming the 26.8 is milliamps, that means 687 to 731 ohms at 200F. The best way to verify a gauge is to get a meat thermometer from your local store.

Oil pressure sender:
60lb unit
0 psi = 0.0 to 1.0 ohm
15 psi = 2.75 to 3.5 ohm
30 psi = 14.5 to 16.5 ohm
60 psi = 28.0 to 31.0 ohm

120lb unit
0 psi = 0.0 to 1.0 ohm
10 psi = 1.5 to 3.0 ohm
70 psi = 16.5 to 18.5 ohm