Oil Level Sensor

[Alan Serven]

Engine/system: 1994 OMC 175 HP 60-degree V-6

Question: Does anyone know how to check whether the sensor in the oil resevoir is good or bad? I get a continuous warning horn as soon as I turn the key to "run" and disconnecting the oil level sensor (or the horn itself) is the only thing that makes it stop. (Disconnecting the high temp warning sensors and the fuel restriction (vacuum) switch have no effect.)

I have checked the resistance across the leads with the sensor installed and am reading about 2100 ohms.

I hate to just have to go buy one and swap it out to see if that really is the problem.

Alan

 

[imported_lorin]

Re: Oil Level Sensor

The sensor is a float switch. When it drops to a certain level the horn goes off. Open up the oil tank from the top and lift out the sensor unit. Try raising and lowering the float by hand to see if it works properly (see if it sets off horn when you lower it by hand.)

 

[Texasmark]

Re: Oil Level Sensor

On Merc's the low oil signal is an intermittent beep. When the over temp goes off it's a constant beep.

Haven't looked but both sensors should go to an electronic control box Merc calls a warning module.

Sounds to me more like a warning module problem because the switch is either open or closed and the warning module has to generate the intermittent part of the beep.

So, even if the sensor were shorted, and I don't think 2100 ohms on a 12v ckt constitutes a short (closed-low oil ) condition, the fact that you are getting a solid beep is a clue.

Also, on Mercs, the horn system is supposed to give you a squeak when you first turn the key on to tell you all is well.

I'd go for the module.

Mark

 

[Alan Serven]

Re: Oil Level Sensor

New oil level sensor came in yesterday via UPS. Checked the resistance with the float in the up, or good oil level position, and got a reading over 2MEG ohms. This is compared to the 2100 ohms from the old sender.

Replaced the sender/pickup unit and it seems to have cleared the problem - when I turn the key on now, I just get the normal "chirp".

See my other thread posting on trying to figure out why it won't idle for more than 15 or 20 seconds in neutral before stalling out...