Mercruiser 4.3 electrical diagrams

[asavas]

Hi guys!
I am new on this forum and i need some help.
I am working on a 1989 Welcraft with an 4.3 Mercruiser on it.
does anybody have a electrical diagram so i can find some wires going from the water temperature sensor to the gauge?
I have two sensors: one is on the thermostat body, the other one is close by, on the engine's head. I cannot figure that out, which are the wires for them.
The engine serial number is:0C464830.
Thank you!

 

[wellcraft-classic210]

You may be able to find one here http://boatinfo.no/lib/library.html


Its a fairly simple ckt -- the wire color at your sensor is likely the same at your temp gauge


12 volts applied at the gauge routs current through the sensor which is a resistor that varies with temperature. As the temperature rises -- sensor resistance drops -- Current through the gauge and sensor increase and the gauge needle rises.

1 quick test-- Grounding the wire at the sensor should peg the gauge needle at full.