1993 yamaha 115tlrr engine oil tank overflowing...Please help....

Motor oil tank is overflowing. I have checked some things and this is what I have found. I checked the continuity of the engine "oil level gauge assembly" and it checks out ok. With key to acc the remote oil pump turns on and starts filling engine tank even though engine tank is already full. I unplugged engine oil tank harness and pump still comes on and wants to overfill engine tank. I unplugged harness at remote tank and have 12vdc at brown wire. This is whats confusing. I'm told the blue wire to ground will start the pump (correct me if i'm wrong). My fluke digital meter shows no ground on blue wire yet motor runs and pumps oil to engine tank?? Emergency switch tests ok but other stuff goes on inside the sealed "oil control unit" just not sure what. I believe the other two wires black and black/red at the remote tank are for low level alarm and should not be affecting my problem. Or could it?? Is the switch switching 12vdc or switching ground? If its switching ground could the blue be grounding to one of the float wires starting the pump. Testing thing at this point are difficult since the motor is at camp 250 miles away. Also the tilt switch located on the cowl will not work in the down position. I mention this because my manual shows the wiring also going to the (oil control unit). I did not see a plug for the tilt switch id goes into harness and disappears. Thank you for those who took the time to read and respond...

Had the same problem with my 86 ETLJ several years ago. The issue was a bad "shut off switch" on oil tank on engine. It's like a float switch that shuts off the pump when the oil in the tank on the engine reaches a given level. It's been so long ago that I don't recall the specifics, but if you check the parts diagram for your engine you should be able to find the switch to which I am referring. It was a simple and inexpensive repair. Perhaps someone else in the forum can help with more detail.

As I said above I checked that float switch and it checks out ok. That being said it could be an intermittent problem and I may change it any way. I just hate shot gunning a problem. The float switch is $100 dollars but i'm sure a service call would be much more. I have purchased a oil control unit so if that isn't it I will try the float switch. I appreciate the response...

You don't seem to get much in the line of responses here. This is what I have done so far. As mentioned above Main oil tank is overflowing and float switch inside main oil tank checks out ok. What I did find is no washer on the bottom of the strainer / float switch inside main oil tank. I bought one and installed it, I also replaced the oil control unit. I found one NOS for $80 on e-bay.. I have put about 3 hours on the motor and no overfilling so far. I will update if problem resurfaces.

Did you check the float switch ??, Sorry only kidding.
If the problem comes back than I would look at wiring. What is the switch doing ? Is it putting a ground for the motor. If a wire could be at times shorting out before the float it will run the tank (main ) motor on.

Well i just got back from the lake and the main oil tank will not refill automatically. I was riding along and the alarm started sounding so I popped the cowl and found the oil level at the low mark. I am able to re-fill using the emergency toggle switch. So now I have a new problem. I had to use the emergency switch twice ( one refill every 20-25 miles). You ask whats the switch doing? On the bench last winter wires W-B show continuity from top down 1/4 inch (stop fill), wires W-Br show continuity down 1-3/8 inch - 1-5/8 inch (start fill), and wires W-R show continuity 2-3/16 inch - 2-1/4 inch down (low alarm). These all fell within the repair manual specifications. I will pull and bench test again later this month. This new problem started with the replacement of the oil control unit??? This issue is a little more tolerable than an overflowing issue.The B (black)wire goes to ground in the schematic so the Br wire must tie into the ground of the remote oil pump. I also see the Br going into the CDI unit???

mikeroc said:

Well i just got back from the lake and the main oil tank will not refill automatically. I was riding along and the alarm started sounding so I popped the cowl and found the oil level at the low mark. I am able to re-fill using the emergency toggle switch. So now I have a new problem. I had to use the emergency switch twice ( one refill every 20-25 miles). You ask whats the switch doing? On the bench last winter wires W-B show continuity from top down 1/4 inch (stop fill), wires W-Br show continuity down 1-3/8 inch - 1-5/8 inch (start fill), and wires W-R show continuity 2-3/16 inch - 2-1/4 inch down (low alarm). These all fell within the repair manual specifications. I will pull and bench test again later this month. This new problem started with the replacement of the oil control unit??? This issue is a little more tolerable than an overflowing issue.The B (black)wire goes to ground in the schematic so the Br wire must tie into the ground of the remote oil pump. I also see the Br going into the CDI unit???

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Here's what happen to me. I have twin 150's . The alarm went off and oil was not filling the tank on the engine . I swapped the tank units on the engine and it never repeated . Was I lucky or what.
Something could be learned from this.
Your problem before was over filling and now not filling.
With out a wire print in front of me it's hard to figure what you checked out but i'm sure it checked OK.
I think you have a bad wiring. Before it may have been shorting and ran the pump and now it's open and will not run .Check the plug and look at the pins. Remove them if you can and look at them. Trace the wires as far back as you can looking for chafing . Or if you can ring out the wires with a OHM meter and wiggle the wires as you do this to see if any wire opens . Put one meter lead end on the engine block and to each pin and see if anything is shorted. Here again a wiring print will come in handy so you will know what plug to disconnect. Also with the correct plug disconnected jumper pins and ring out pin to pin at the tank plug to see if they are open or shorted. It's going to be time consuming. I worked for a airline (AA) for 38 years in avionics and that's what we did mostly did looking for a bad wiring. But we had good wiring prints to follow.
good luck and hope I helped in some way.
Bob