Mercury oil system

[zelmo]

Optimax 200
Model # 1200D73DD
Serial Number 1B044654

I have always used Quicksilver DFI oil.

I got a warning the last time out that I was running on the oil reserve tank. Since the main oil tank on the boat was about half full I figured I had a problem moving oil from it to the motor.

What I found was that the intake screen in the main tank was clogged with some sort of jelly like substance. I probed the bottom of the tank and it has a layer of this gunk that needs to be cleaned out. In searching around I found one comment that said Mercury had a problem with an additive in the oil in 2015 that can cause this. Can anyone confirm that?

I cleaned the intake screen and confirmed that I had oil leaving the tank. It took a while for it to work its way back up to the reserve tank on the motor, and the whole time I was getting the alarm telling me I was at 80% of reserve. My understanding of the system is that there is a float in that reservoir that gives that reading. What I don't understand is why the alarm stopped as soon as I had oil entering the reservoir. It was still at the same level it was at before and the flow was not heavy. I ran it at idle on the muffs for a while and when I got tired of waiting for it to fill completely I topped it off manually.

Is the alarm triggered by pressure in the tank or does the float move up just from some flow?

[SilverFox579]

The alarm is triggered by the float in the engine reservoir. You may also have had some gunk in your feed line from the remote which might be why it took a while to work back to the reserve. You say you cleaned the intake screen, which is good, but if you didn't also drain and clean the layer of gunk you found in your remote tank, this will happen again.

[zelmo]

The alarm is triggered by the float in the engine reservoir.

So why did the alarm stop when I got oil flowing into the reservoir even though the level had not increased?

but if you didn't also drain and clean the layer of gunk you found in your remote tank, this will happen again.

While I didn't say it in my post I did clean the gunk out. I would like to know what caused it so I can possibly keep it from happening again.

This is what the gunk looked like. I took about 5 ladles of it out.

Gunk.JPG

[EuropeanAM]

I have seen no problems with DFI oil congealing like that. The ONLY time I've had this type of material found on the pickup screen it was due to MOISTURE (possibly from a funnel that was being used), or from mixing different types of oils.

Good that you found/identified this and cleaned it out!

The float/sensor are merely an "OPEN or CLOSED" circuit signal. Quite likely that you were right on the edge of the triggering area and the slightest bit of oil closed the circuit.

Of course, make sure the air is bled from the engine-mounted tank.

[SilverFox579]

I have seen no problems with DFI oil congealing like that. The ONLY time I've had this type of material found on the pickup screen it was due to MOISTURE (possibly from a funnel that was being used), or from mixing different types of oils.

Good that you found/identified this and cleaned it out!

The float/sensor are merely an "OPEN or CLOSED" circuit signal. Quite likely that you were right on the edge of the triggering area and the slightest bit of oil closed the circuit.

Of course, make sure the air is bled from the engine-mounted tank.

What I suspect happened too.

[zelmo]

I have seen no problems with DFI oil congealing like that. The ONLY time I've had this type of material found on the pickup screen it was due to MOISTURE (possibly from a funnel that was being used), or from mixing different types of oils.

Well, I am able to pour right from the container into the tank and don't use a funnel. I have never used anything other than Quicksilver DFI over the 13 years I have had the boat. For the first 7 years the boat was stored outside in the summer and indoors in the winter. Since then it has been kept year round in a dry, albeit unheated, garage year round. I guess condensation inside the tank is possible.

The float/sensor are merely an "OPEN or CLOSED" circuit signal. Quite likely that you were right on the edge of the triggering area and the slightest bit of oil closed the circuit.

When I was on the water the Smartcraft gauge gave me the warning and said I had 100% reserve. When I got off the water I still had the warning and was down to 80% reserve.

As I was trouble shooting in the driveway I had the warning and the 80% reading the entire time I was bleeding the line to the reserve reservoir. As soon as I got oil flowing into the tank the alarm stopped. If the float/sensor is just OPEN or CLOSED why would it show percentages and turn the alarm off with a slight increase in oil level? Seems to me that there must be more than that going on.

[EuropeanAM]

Percentages are based off the PCM's Oil Delivery Strategy. Since the PCM "knows" how much oil it is delivering, it begins computing how much oil remains when the "OPEN CIRCUIT" signal is received (that's why it went from 80% to "no warning" when you filled the tank and the switch generated a CLOSED circuit signal).

The above logic permits the PCM to begin limiting engine power in an effort to preserve the engine as the remaining oil in the engine-mounted tank is consumed.

[zelmo]

Got it. Thank you.