2001 Yamaha 150 TXRZ Oil tank alarm issues

[kheber7]

I'm hoping someone can help me out. I have a 2001 Yamaha 150 TXRZ 2 stroke with Oil injection. The alarm goes off once I turn the key on. At first we thought the it was the Oil Level Gauge Assembly in the oil tank on the engine. Change that out and alarm stills goes off. When we un plug the wire harness on to the Oil gauge sensor on in the sub tank in the boat, the alarm goes off. We narrowed down to the Oil Gauge Sensor in the sub tank. When we took it out and manually move the float, when the float was up the alarm sounds off. When we push the float down, the alarms goes off. This is opposite on how it should work! But, when the float is down, the oil pump doesn't work. So I have the problem where the oil pump is working correctly when the float is up, but the alarm sounds. When the alarms sounds it shuts the motor down to safe mode! Right now, I have the sensor rigged with the sensor float down so the alarm doesn't sound off and just using the manual pump on the engine which works fine. I was hoping it was the oil sensor that was bad, so I bought a new one. Same problem. It keeps throwing a ground signal to the alarm when the float is up instead of down. There was one other post on this site from someone who had the same problem, but there was no resolution to the problem. My next steps is to change out the CDI but before I spend money on that, I am hoping someone can help point me in the right direction. Is it truly the CDI unit, the wiring harness to the CDI unit or is the alarm bad? If someone can shed light on this, I'd appreciate it! Thanks!

 

[ClassicAQ]

If I've read you correctly, you've replaced oil level sensors in both engine main oil tank and reserve oil tank but are still getting alarm when turning key switch to ON position? I'm gonna assume the oil in the main tank is in between the 2 level lines, as well as sufficient oil level in the reserve tank. Otherwise the alarm will sound when keyed ON (if reserve tank pump does not fill main tank).

You've ruled out bad sensors since you've replaced both main tank and reserve tank sensors. And there is enough oil in both tanks to not cause low oil level alarm. So I'd next focus on the wiring, specifically the oil harness connecting the reserve tank to engine side harness. I can't explain why when the float is up the alarm activates and when the float is down the alarm does not activate. The tank's sensor harness can only be plugged in one way the oil harness. Volt drop test the system, working from the reserve tank sensor back to engine side harness. Brown is power, blue is ground. With the float in the up position, you're looking for the ground when there shouldn't be a ground.

 

[kheber7]

ClassicAQ, thanks for the response. Yes both Oil tanks are full. The pump does work when plugged when the oil tank on the motor is low. I drained the tank on the engine and turned the key, the alarm went off, bc it was low, pump kicked on and filled the tank up to the top line then turned off, but the alarm still sounded off. I will check the harness from the Oil sensor on the reserve tank in the boat to the engine. We did check and found that a ground is being thrown back to the alarm when the float on the sensor is UP instead of when its Down. That's what puzzles me. So, I am think that a bad ground is coming from the harness or the CDI unit.

 

[Walidfl]

had a similar problem a few years ago. I took the sensor out of the remote 2.5gal tank and cleaned it well. I think that the slide was sticking and not sliding up the shaft indicating that the remote tank was full.