2004 Yamaha 150hp oil sensor light

[beckoning]

G3 (Yamaha) 18.5' boat with 2004 150hp 4-stroke Yamaha, less than 500 hrs. All ran perfect last year. Ran perfect on the trailer with hose connected to water supply. Put boat in the water, started with engine tilted up, then lowered the tilt. Ran great, but the oil level sensor light stays lit. Was it because I started it tilted? Oil is to the top of the dipstick "full" mark. Where is the oil pressure/level sensor located on the motor? Ideas

 

[boscoe99]

No oil level sensor. Only an oil pressure sensor.

You made no mention of an alarm sounding or the motor going into RPM reduction mode. Usually the light, the alarm and the reduction mode all occur at the same time.

Is the light within a Yamaha tachometer or is it a standalone light?

 

[99yam40]

I hope it was a wiring connection problem or bad sensor and not really low oil pressure.
that would be bad on the power head

 

[boscoe99]

Now that I think about it the OP probably had low oil pressure given that hte started with the motor tilted up. Running the motor down probably alleviated the low oil pressure but the light might have remain lit until the motor was turned off. At the next start cycle the light might not be illuminated. Still does not explain the lack of a warning horn.

Yamaha might have to come up with another sensor to prevent a tilted motor from being cranked.

 

[beckoning]

Now that I think about it the OP probably had low oil pressure given that hte started with the motor tilted up. Running the motor down probably alleviated the low oil pressure but the light might have remain lit until the motor was turned off. At the next start cycle the light might not be illuminated. Still does not explain the lack of a warning horn.

Yamaha might have to come up with another sensor to prevent a tilted motor from being cranked.

Now, as I recall, there was a very brief horn upon starting. After putting the boat in the water, I just went to my dock (3/4 mile) at 1500-1800 rpm +/- through the No Wake area. Tomorrow, I will start with the engine down to see if the light+horn go on. Oil level is top of range on the stick.

I agree with 99Yam. Low oil pressure is disastrous, but like all 4-strokes, I presume the Yamaha 150 (2004) has a mechanically driven oil pump, so the likelihood of low pressure with a full crankcase could only be caused by a blockage of the oil pickup or a bad sensor. Tammy sat all winter with oil and the crankcase completely sealed off, so I'm baffled if the OP light returns. Maybe a bad sending unit?

 

[99yam40]

I wonder if being tilted up allowed the oil pump pick up to suck air.

also does anyone know if the oil pressure sensor is a switch or maybe something that sends a variable signal telling how high the pressure is.
could be mapped to RPM and pressure being within a certain range

this motor has an ECU so my bet is it is a sensor not a switch

 

[boscoe99]

If the motor was tilted up when started it is not unreasonable to think the pick up tube will be out of the oil.

I am still confused as to whether the light stayed lit or not.

What light?