Oil transfer on an S150

[zigzag03]

Greetings, I am working with an S150tlrw that doesn't transfer oil from the boat tank to the engine tank. It will transfer it with the manual switch at the back of the motor above the "computer", which says to me that the wiring between engine and tank is ok and the pump is ok. . I pulled the sensor from the engine tank, it's 4 wires. Between the black wire and the blue/white, I can see it switch continuity as the float is raised and lowered, and I'm guessing that this function turns on the low oil alarm, which does work. The other 2 wires are blue/red and blue/green, and I can't get them to respond either between themselves or with the black ground.
My thought is that perhaps these wires allow the computer to turn on the pump, and this is my question.
Should I be able to see some reaction across those other 2 wires and is the lack of it an indication of a bad sensor? My options, short of an informed answer, would be to swap it out for $136 and see what happens. The other alternative is a very expensive "computer" which appears to be the only other component that could cause the issue. I've inspected all the connections at the bottom of the computer and they all look good. What say you Yammy guys? Thanks, ZZ03

 

[boscoe99]

The sensor has three switches in it. SW1 at the top, SW2 in the middle and SW3 at the bottom.

The switches are activated by the float. Let's start with the float at the top. SW1 is closed. When the float falls to a point it will close SW2. This lets the ECU know that oil is needed. The ECU will turn on the oil pump. Oil will flow from the remote tank to the main engine mounted tank. The float will rise as oil is added. When the float rises it will cause SW1 to close. This tells the ECU the tank is full and to stop the pump.

HOWEVER. When SW2 closes the ECU first checks the remote tank to verify it has sufficient oil in it. If so, it will tell the pump to run. If not, it will not tell the pump to run.

If and when the float drops to near the bottom of the main tank SW3 will close. The alarm will sound, the motor will go into RPM reduction mode, and depending upon the tachometer lights will flash/illuminate or icons will flash.

The service manual will provide the procedure to test the main tank sensor/switches and the remote tank sensor/switch.

 

[zigzag03]

Thanks Boscoe thats helpful. So its entirely possible that the sensor in the remote tank could have an issue, Wouldn't that give an alarm of its own though? Or is that sensor also multifunction? In any case, I don't have a service manual, not keen on buying one frankly. At 61 and out of the business, I'm trying to get rid of marine related stuff, not collect more. I'll ask my neighbor if he'd like to buy one, after all, its his boat. Thanks again.

 

[boscoe99]

Does the boat have Yamaha gauges installed? If so, a Yamaha tachometer will indicate that the remote tank is low on oil. As noted, when the remote tank gets low the auto-transfer function will not operate.

 

[zigzag03]

Thanks man this is very helpful. This unit has the LCD tach and speedo, and they are so bleached out they're barely readable in daylight, When I lifted the sender out of the engine tank (it was full) it set off the horn, but I didn't really study the gauge to see what was actually being indicated. In fact, I didn't know these gauges had this much capability. Let me get back to the boat for further study. It seems to me that there are three things indicated, oil, temp and,,, voltage maybe? I didn't see an actual level indication as this chart shows. Film at 11 thx again