HPDI oil tank(s) question

[spinkick63]

Took the boat out recently and everything worked. Main oil tank was at maximum level. Remote tank was at max level as well. I know the pump is working as the toggle switch behind the tank pumped oil. Whether it was pumping enough remains to be seen. I did make sure the arrows on the remote tank and cap were lined up. The oil level float moved freely and the basket strainer was unobstructed.

How low does the remote tank need to get before it starts drawing oil from the main tank? I noticed the remote tank level dropped from max to somewhere just below center between min/max lines. Main tank did not appear to change levels.

Does it sound like it is working as designed? Am I starting to have oil pump issues?

Thanks in advance

[yam911]

The main tank is on the motor. The remote tank is in the boat.

The main tank has three float activated switches in it. One at the top, one in the middle and one at the bottom. The float falling and rising triggers the switches to open and close.

Starting with the tank being filled, the top switch is closed. When the oil level drops to the middle of the tank, the middle switch closes. This tells the ECU that it needs to turn on the oil pump in the remote tank so as to fill the main tank back up. When oil is pumped to the main tank from the remote tank and the main oil tank is full, the top switch closes. This tells the ECU to turn off the remote tank oil pump.

This cycle repeats itself over and over again with the operator not being aware of it happening.

At some point the oil in the remote tank will get pretty low. A switch activated by a float in the remote tank then opens. The switch opening tells the ECU to stop the automatic oil transfer system. A light or icon in a Yamaha tachometer will tell the operator that it is time to add oil to the remote tank.

If the motor continues to run with out the main oil tank being replenished (because the automatic system has been disabled) then when the main tank gets low on oil (bottom switch closes) three things will happen. The motor will go into RPM reduction mode. The warning horn will sound. The Yamaha tachometer will turn on the low main oil tank warning light. Some boats have a dash mounted low oil light.

Woe be unto he who continues to let the motor run with the alarms activated. At some point the main oil tank will be out of oil. Motors don't run so well without oil.

If you don't have any caution or warning lights, if the alarm is not sounding and the motor is not going into RPM reduction mode, I don't see you having a problem.

Easy enough to test the system if you want to.

[spinkick63]

oops. Had my tank descriptions backwards.

Thanks for the info. I had no alarms. I was just surprised the (corrected terms) main tank got as low as it did.