1992 200hp - Oil Transfer Issue

[mako211cc]

Year: 1992
Model: 200TXRQ, 200hp 2.6L

I have read almost all of the "oil transfer" threads and am at a loss.

Prior to alarm: triangle over GREEN as baseline, engine oil tank full.

Symptoms:
Oil will not transfer from aux tank to engine tank automatically; alarm sounds with flashing triangles over Red/Yellow/Green (engine tank is low)
-Emergency switch DOES activate the transfer pump to fill engine tank.
-Trim gauge DOES work.

Attempted resolutions:
-Replaced engine oil level sensor
-Replaced trim sensor
-Replaced inline filter, although this would not explain why the emergency switch does work

No resolution of above alarms and issue with automatic transfer. This, per the attached diagram, leads to replacing the ECU.

Any thoughts? Where else should I look? Thank you for your efforts!

[mako211cc]

Yes, I have read the often quoted RodBolt's:

Lets clear up some mis information on the V6 yamaha oiling.
the trim sender is ONLY used on the 1990 to 1995 2.6L V6. only.
the 3.1Lv motors ALWAYS used a pulser coil signal and automatic oil transfer will ONLY occur if the flywheel is turning. the 2.6LV6 from 1996 and up use the same signal to transfer and NOT the trim sender.
V4 from about 2004 and up do the same as the 2.6 and 3.1 motors.
the remote tank switch,also known in the manual as SWB, is closed(float up) when the tank is over about 30% full and will give a green indicate on the tach.

when SWB is open(float down) it means either a wire broke or the remote tank is less than about 30% and the yellow lamp is lit(center bar or arrow) and automatic transfer is prohibited.

there is now enough oil in the remote tank for two manual transfers.
now for the engine tank switchs.

when the float is all the way up SW1 is closed sending a transfer pump OFF command to the ecu.

float about midpoint and SW2 closes sending the ECU a transfer pump ON command.

this on off cycle continues for the life of the engine under normal conditions.
in the event of a malfunction,or oil system initilization after maint, the SW3 (lowest) switch closes the ECU is comanded to set the alarm,(gray wire to the harness pink grounded)commands the ECU to set RPM limits to about 2000 RPM max.

sets the DES switch in the case of twins to limit the second engine as well.
commands the ECU to try transfering again in case SW2 has failed, and sets the command,grounds the green red wire,to illuminate red or far left bar or arrow.

in the event of system maint,or system initilize you have oil in the remote and none in the engine tank. at key on all the bars,arrows or lights will illuminate and transfer is commanded for 180 seconds and will continue until either the 180 seconds times out or the SW1 switch closes.
in the event of a resrition,either the remote tank oil filter or the hose is pinched,the normal scene is the boat will run normally for a few miles,alarm and fall on its face.

this is because the oil can be consumed by the engine at speed faster than it can transfer.

however because SWB is closed and SW3 is closed oil is trying to transfer and at low speed SW3 opens,alarm quits in a few seconds and all seems normal until a mile or two later the same thing happens.

NEVER NEVER EVER pull out the switch and filter screen from the engine tank unless the engine tank has been FULLY drained first.
just dont do it or you CAN destroy a power head.
the above poster did not fix an alarm issue.
trust me.

there is nothing to short on that alarm.
at key on the alarm yellow wire has 12V applied.
the ground is supplied,when commanded, by the ECU or a temp switch,via the pink wire in the 10 pin main harness.a quick test on the v4 and v6 alarms is to pull the stop lanyard and crank the motor.
if the horn sounds while cranking all is good, if it does not then test the alarm and circuits for faults. there is a lot of mis conception and downright lack of knowledge even among yamaha techs. in fact on the master tech exam its one of the most missed 20 question section.
the remote tank NEVER EVER controls the alarm.

it simply alerts the operator as to oil level remaining.
and remember NEVER NEVER EVER remove the engine switch assy unless the engine tank has been FULLY drained.
NEVER EVER reuse that 40 cent seal between the engine tank screen and the tank.

ALWAYS retrieve that seal if the screen is removed.
what most likely happened is the remote oil tank filter is clogging and once off plane with the key still on the engine tank was refilling while the wiring was being messed with and the alarm tone quit,then at throttle up it ran a few miles and the process was repeated.

[rodbolt17]

you are misreading the visual indicates.
green means the ECU "sees" remote tank level ok, NOT engine tank.
yellow lamp the ECU "sees" remote oil tank level insufficient for automatic transfer.
red the ECU sees oil level in the ngine tank is low.
now that that is clear.
three bars flashing indicates oil level in the remote is ok,oil level in the engine tank is low.
SWB is still closed(remote tank switch) yet oil level in the engine is low.
does the trim sender work?
is the remote oil tank filter clogged?
what are the wire colors on your engine oil tank switch?

[rodbolt17]

also remember.
there are NO sensors in the yamaha oiling system.
just on/off switchs.

[mako211cc]

Thanks for the assistance.

Per above:
1. Replaced the trim sensor
2. Replaced the remote oil tank filter
3. Replaced the "oil level sensor" / switch on the engine tank

The pump will operate with the emergency switch. It will not when I move the float on the engine tank's oil level sensor.

Per the diagram, I am down to te ECU. Correct?

[mako211cc]

No outside of the box thoughts?

[rodbolt17]

other than there are no sensors nor out of the box syuff.
this system works and works well.
however careful testing is required as an ECU is rather expensive and they rarely fail.
drain the engine tank,make sure the remote is at least 1/2 full.
turn the key on.
you should have 3 bars/lights flashing an audible alarm and the transfer pump should turn on for 180 seconds.
do you know how to do a voltage drop test?

[mako211cc]

I understand it is a question of semantics, but Yamaha refers to to the engine oil tank switch as the "oil level sensor."

Yes, I will check the voltages this weekend. The local shop is scheduled to look at it next week.

[rodbolt17]

does your tach respond as I asked?
and what wire colors does your engine switch have?

[mako211cc]

Yes, the tach responds as you asked.

Colors on the engine switch I will obtain.

[mako211cc]

Problem solved: As I suspected based on the Yamaha flow sheet, but as I doubted based on the "ECUs never fail" dogma, I replaced the ECU and the engine's oil tank fills as expected. 10 minute job to swap the ECU.

Of note, there are plenty of good deals on used ECUs on ebay. I found one with a 60 day warranty for $175 shipped. Works for me.

Follow the diagram in post 1.