oil sensor help

[linusb]

Engine is an 84 model 115 hp Yamaha. My remote oil pump stays on. Mechanic said the main tank oil sensor is likely bad. Looks like an easy fix...just get a new sensor. In the meantime, can I disconnect the electrical leads to the remote
tank and manually fill the main tank as needed. I will be getting the sensor as soon as possible, but would like to use the boat in the meantime.

I noticed the red quick connect from the sensor to the control unit was disconnected. I hooked them up and upon turning the key to just the on position, the buzzer alarm went off. I disconnected the same lead again. I pulled the main oil sensor part-way out of the tank just to see what it looked like basically and pushed it back into place. Turned the key to the on position again and the pump turned on just as before. This time though, when the pressure built up enough it popped the oil sensor off the top. Not sure where it was leaking out before, but I assume it would have been the breather hose.

Looking at the manual (aftermarket manual) it shows a circlip at the base of the sensor unit. Not sure if this applies to my year model or
not but I see no possible way of removing or securing any time of clip to the base of the sensor unit. What can I do to better secure the sensor onto the tank?

I'm now feeling a little nervous about replacing this part myself.

[Hamfisted]

They sell the whole unit and you just pop out the old and push in the new and plug in the harness. You can order from Boats.net online if its more convienient or stop by your local dealer.


Mike

[linusb]

Thanks for the info. For some reason, when I pull up the "oil tank" diagram, it is different than what I have. If I pull up the "oil tank conversion" or "oil pump" diagram it matches what I have, the latter diagram has a reference when pointing at the oil tank that says grid D-8 Ref#21. No idea what that means. I assume that it is a section of the catalog possibly not covered in this online version.

The Yamaha parts catalong online and the boats.net ones are the same.

[Ken]

linusb,
You might consider getting a Yamaha shop manual in addition to that after-market one, if you can find one for that '84.
Good luck [img]smile.gif[/img] ,
Ken K

[linusb]

I've re-looked the issue. Disconnected the main sensor completely, pulled it out of the tank, disassembled it. The float is working fine, there are no other moving parts. I guess the magnetic switch is inside and don't know enough about those type of switches to know how or why they might go bad. Re-assembled, connected all leads, held the unit up-side down to simulate a full tank, verified that float was at the top of sensor, turned key and pump still ran. I hooked a tester light up to ground and used the probe to ground out the white lead going to the con*****er and the pump still ran.

From what I am understanding, it sounds like my con*****er unit would be bad. Either that or a bad ground to the wiring of the remote tank.

Just looked that con*****er up on boats.net and it is almost $300. Not really wanting to shell out that kind of money because I also have some trim/tilt issues that need to be addressed as well. Now I'm thinking that I should disable the oil injection and not worry about it at all.

I'm a bit frustrated since I just bought this boat and am starting to see the wisdom in buying a new boat.

[jb123]

i assume youve checked all harness ends for corrosion? they can be found quite cheap and if im not mistaken the oil control unit goes for bout $175,at least thats what my `89 v-6 unit went for.

[linusb]

I checked the ends between the sensor and the con*****er. They seem okay.

I see some references to a filter causing problems with the sensor inside the main oil tank. In taking my sensor out, I didn't see any filter like that. Would that be something in newer motors?

[Ken]

linusb,
I believe the con*****er provides a ground path for the remote pump when the sensor calls for more oil. I would go to the remote pump and disconnect that signal wire to the con*****er and turn ignition on and see if the pump still pumps by itself. If it does, then the pump is getting a false ground from somewhere - or it could be grounding out between the pump and the con*****er.
Good luck [img]smile.gif[/img] ,
Ken K

[dyount]

I have the same problem/same engine(84 115). For now I have disconnected the blue wire at the control unit(supposed to only be grounded under alarm condition). I pop the cowl and reconnect it to run the pump when the upper tank gets low.

After extensive testing with an OHM meter I'm sure the sensor works like it should and convinced that it's the control unit. I'm a little short on cash at the moment, but will end up buying a new unit in the next two weeks. $275.00 plus shipping is the best price so far.

Now it's a matter of which one of us forks out the cash first. I'll post as soon as I know this did the trick and hope you'll do the same.

Luck to you.....

[linusb]

I'm taking the boat to a mechanic today. I talked to him on the phone and he recommended disabling the oil injection unit saying that at the age of the motor, it is past due. I'm not sure what the danger of the system actually failing at this piont is, however, I've dealt with the whole oil mixing thing while riding motocross and it's not that big a deal to me. I think I'm gonna go that route and know that from a lubrication standpoint, I am covered.

[Hamfisted]

I think I'd take it to the dealer rather than that particular mechanic. It may just be a grounding short in the oil pump harness anyway.


Mike

[dyount]

Got It!

Turns out that not only was the oil control unit at fault the oil sensor was intermittently sticky as well.

Before deciding to replace the oil control unit I recommend that you test as follows -

Tilt the engine down to the point that the upper oil tank is as level as you can get it and completly full. Disconnect the white and black wires from the oil sensor and verify continuity (switched closed)on the oil sensor side (means the sensor is working).

Connect the white and black wires from the control unit (the ones that go to the sensor). Turn on the key and if the lower tank continues to pump to the upper when the tank is full, then the control unit is definately at fault.

My secondary issue with the oil sensor was corrected by lightly sanding the sensor probe and the inside of the magnetic float using #600 grit paper. I noted that prior to sanding I could feel abrasive type friction while rotating the float as I ran it up and down the probe.

[Ken]

dyount,
Nice troubleshooting there - glad you found your problem [img]smile.gif[/img] ,
Ken K

[dyount]

Appreciate that Ken. Also, Linusb should note that I neglected in my posting to recognize the possibility of a ground short between the Control unit and pump (Ken mentions this possibility in an earlier post).

To verify, disconnect the blue wire at the control unit to the pump. The pump should stop immediately.

Thanks to all, this forum has been extreamly helpful...

-Dave

[rkj1974]

Hello from new guy. Anyway, thanks for this info. I just found this site tonight doing a search for Yamaha parts. We bought an as-is boat yesterday with a motor problem. And as luck would have it, the problem discussed here is the problem it has. When you turn on the motor it pumps oil into the oil tank until the top pops off. And the motor is of course in "safe" mode and won't go over 2000rpm. Your info here will give us a head start in fixing the problem. Thanks again.