Bukh 20 warning lights Charging. Oil. Water

[davidmh]

Should the red chargiing lamp, the orange oil pressure lamp and the blue water temperature lamp all go on when you switch the engine key on.? On my Bukh only the red one lights. The engine runs perfectly, the electric oil pressure gauge and electric water temperature gauge both show the correct values.
If the oil and water lamps do not light up anyone like to suggest what could be the problem? The bulbs seen to be in a small individual rectangular plastic housing If I put a meter across each of the 3 bulb terminals with everything switched off should I get a continuity reading on gthe red one and zero on the other two. if they are all the same then the bubs are good. The wiring all looks good. Not sure how long it has been like that because when I stop and start the engine i caanot see the lights.
Any thoughts qwelcome.

 

[VicS]

The red and orange lights should come on at switch on and go out once the engine is running..
It may need a blip of the throttle to extinguish the red and with an old worn engine that has not run for a while it may be a few moments before the orange one goes out.both should be off while the engine is actually in use.
The blue will only come on if the engine is overheated.
The orange one may not be coming on because the bulb has failed (least likely), the sensor is defective, or because of a bad connection somewhere ( most likely).

 

[James_Calvert]

There's an important function attached to the blue warning light and associated buzzer.

If you forget to disengage the stop solenoid, after the engine has stopped, it will get really hot, and destroy itself. If the oil warning system is working, the light and buzzer will sound once the oil pressure falls in the stopped engine.

 

[davidmh]

Thanks for those answers. I have looked carefully at the workshop manual now and the Bukh has two circuits for the oil pressure and 2 for the water temperature which does explain why the lamps do not work but the gauges do. The temperature sender has 2 spade connections one is for the gauge and one is for the lamp. For the oil there is one switch on the sump which connectes to the lamp and another tranduce on an oil pipe that goes to the gauge. There is a whole bundle of wires that go into a connection block near the engine, not covered and looks messy. I will probe around with a meter and hopefully I will find a dud wire somewhere. The chances of both bulbs blowing together is quite remote but I wil check that as well.

Thanks
David