Low Oil Level Alarm with Full Tank...(Boscoe chim in)

[Jason2tpa]

you really need to have a service manual for your motor.

I have the service and owners manual for my motor. Neither provide trouble shooting for this particular scenario. And yes, I'll continue to search online for the solution and certain I'll find it. Either someone will be kind enough to walk me through the steps on this forum, or I'll come across the answer elsewhere.

Either way, appreciate the tip on checking the ground.

[99yam40]

1st see if it has 12 volts to it

all the Yamaha manuals I have seen show the switches involved and have troubleshooting steps in them

[rodbolt17]

I have beat this to death on this and other forums.
it is a stupidly simple DC 12V motor.
at key on the yellow wire from the switch provides 12+DC on the brown wire to the pump.
the control unit supplies the ground path based on the position of the 4 switchs.

just like the light switch on your wall.

can you lose the positive current path?
can you lose the negative current path?
can the motor(light bulb) die?

yes.

however with a simple voltage drop test all are easy to find.
typically takes less than 15 min to find the issue.

and yes I have beat to death how to do a voltage drop test on this and other forums.

[pstephens46]

Prior directions from Rodbolt on voltage drop testing:

your looking for a voltage DROP not battery voltage.

at the + battery TERMINAL not cable attach one lead using the DC scale. the other lead will go to the + terminal on the starter again the stud not the cable end.
turn on the key, you should see less than .5V,turn the key to start,should still see less than .7v.

now using the same autoranging DC volt scale attach one lead to the - stud at the battery the other to a good block ground.
turn on the key, you should see less than .5 V try starting it and you should still read less than .5v.

if the + wire reads more than .7V start backing up with the lead that was on the starter battery terminal IE battery switch's and such until it reads less than .7 while loaded.

if the - cable reads more than .5V start backing down the - cable looking for junctions and splices that may have failed.

what we are doing is finding the voltage DROP acrossed a resistance.

take the ground wire and visualize the circuit, barring any terminal junctions it is a straight piece of wire from point a (battery stud) to point B the ground wire attachment at the block.
the only resistance in a perfect circuit would be the resistance of the copper,very low.

now when we operate,or try to, the circuit we are using the electrical pressure,measured in volts, to force electrons(amps) down the wire.
if all is perfect the pressure drop from a to b will be a minimal loss maybe .5V or less.
now if we have a bad spot in the cable(a resistance) we may drop 5-8 or more volts ACROSS that resistor.

loose corroded cable to terminal connections can act as a resistor as can bad cables,bad cable to cable end or any junctions between point a and b.[/QUOTE]

[pstephens46]

Obviously this was for a cranking problem. These directions are easily enough translated to apply to your pump issues.

[boscoe99]

Forgot to mention this...after learning the main tank wasn't filling, while the key remained in the ON position I flipped on the emergency pump switch. It's technical name is the Control Unit Assy, located under the engines main tank.

This also did not feed oil into the main tank. I haven't found the wiring diagram for that accessory, so i'm not sure how its powered and/or if its power source is the same as the remote tanks power supply.

Thought this extra info would be of some use for your advice. Thanks.

With the key on you should have 12 volts applied to the brown wire at the pump. With the toggle switch pressed you should have a ground applied to the blue wire at the pump. If you do, and the pump does not run, the pump is at fault. If you don't have the volts and the ground at the pump then it could be a wiring issue, a connector issue, a voltage supply issue or a ground issue.

Send me your email address and I will send you some diagrams and suggested test procedures.

[Jason2tpa]

Ok guys, appreciate the instructions. Hoping to get over to the boat later to apply those troubleshooting steps.

[Jason2tpa]

Update for those following:

With assistance from boscoe sending me a few sweet wiring schematics, I've narrowed down the issue. Applied 12v and ground directly to pump, it works. Made the same connections to the remote tank harness, pump works. Reconnected the tank then applied 12v and ground directly to engine side of oil harness, pump did not work.

By that time mosquitos got fierce, so i ended there. Gonna perform a few more tests boscoe recommend before calling it a bad oil harness. Good news is a new pump isn't required. Cha ching.

[boscoe99]

Update for those following:

With assistance from boscoe sending me a few sweet wiring schematics, I've narrowed down the issue. Applied 12v and ground directly to pump, it works. Made the same connections to the remote tank harness, pump works. Reconnected the tank then applied 12v and ground directly to engine side of oil harness, pump did not work.

By that time mosquitos got fierce, so i ended there. Gonna perform a few more tests boscoe recommend before calling it a bad oil harness. Good news is a new pump isn't required. Cha ching.

I thought you said the pump did not work when it was powered and grounded via the oil harness?

[Jason2tpa]

I thought you said the pump did not work when it was powered and grounded via the oil harness?

My mistake boscoe...I didnt know the proper part name I was describing. I said "made the same connections to REMOTE TANK HARNESS". The correct part name is OIL LEVEL GAUGE ASSY. Sorry for confusion.

The pump worked when applying 12v and ground directly to the pumps brown/blue pigtail. I then reconnected pigtail, disconnected the oil harness from oil level gauge assy, applied 12v and ground directly to the gauge assy. The pump worked. Reconnected oil harness to oil level gauge assy. Moved the 12v and ground to the engine. Disconnected the ENGINE side of oil harness. Applied 12v and ground directly the oil harness. The pump did not work.

[99yam40]

now would be a good time to see if you have 12v+ to the pump when you turn the key to on when everything is hooked up or when you apply 12v+ to the harness at motor end.

or ohm out the harness wiring to see what is making connections
a wire is a wire, just need to see which ones are making good connection from one end to the other

[Jason2tpa]

now would be a good time to see if you have 12v+ to the pump when you turn the key to on when everything is hooked up or when you apply 12v+ to the harness at motor end.

or ohm out the harness wiring to see what is making connections
a wire is a wire, just need to see which ones are making good connection from one end to the other

Exactly. But I couldn't figure out how to get a test probe into either the engine side power receptacle or the oil harness reserve tank receptacle. They are both female receptacles, so no terminal to touch a probe to or attach jumper clips to. Suggestions?

[DennisG01]

A thin meter probe tip will get into the female side connector. Or, I sometimes use a thin gauge piece of wire, just a few inches long - push that into the female connector and then use alligator clips. Keep the sheathing on, except for a half inch at either end.

[Jason2tpa]

Update:

Sprayed all connections with electronic solvent, wired brush, at tank and at engines connections.

Reconfirmed the oil pump works when I applied direct 12v power and ground to pumps brown/blue pigtails. Reconfirmed the pump works when I applied direct 12v power and ground to the oil level gauge assy. Reconfirmed the pump did not work when I applied direct 12v power and ground to the engine side of oil harness.

Checked the voltage output and ground for the engine harness connector. Contrary to my last post, I was able to get the test probes in far enough for a reading. These are the results when ignition key was turned to ON position:

-Red meter probe to brown receptacle of engine harness, black meter probe to blue receptacle of engine harness ---> 12v

-Red meter probe to brown receptacle of engine harness, black meter probe to engine block ---> 12v

So I'm getting power out of the engine harness connector. I'm getting pump function when 12v and ground is applied directly to pump. The problem must be the harness connecting the engine power source to the pump...the oil harness.

I did one more step, thinking the ground must be bad somewhere in the oil harness because the ground is good at the reserve tank. I turned key ON and did the following:

-Red meter probe to brown receptacle of engine harness, black meter probe to blue terminal of oil harness ---> 0v

So what do y'all think....have I found the culprit?

[rodbolt17]

no
me thinks you still do not understand the relation ship of voltage AND current.

voltage is simply electrical pressure.

current MAKES the device actually work.
use Yamaha part number pap-ercli-p0-00 inserted in the brown and blue wires at the pump bullet connectors and simply do a voltage drop test.

that will tell you witch of the CURRENT paths have excessive resitance.

it is a stupid 12v motor that the module controls a ground path.
lose the 12V supply OR the ground return path and the device simply quits working.