What Is this alarm? Mercury 2001 125hp

[lgaytan]

Can anyone tell me what is this alarm? Is this overheating?

 

[lgaytan]

Ok... According to a YouTube video it should be overheating or oil sensor, I don't think it was overheating I saw good water flow and can touch the block, oil reservoir was full maybe the sensor is badi will have to inspect to be sure.

 

[Texasmark]

Ok... According to a YouTube video it should be overheating or oil sensor, I don't think it was overheating I saw good water flow and can touch the block, oil reservoir was full maybe the sensor is badi will have to inspect to be sure.

In the engine, on my recent engines, the tan with light blue stripe is over temp from the temp sensor to the output connector whereby the low oil is on the light blue white stripe wires (2 ea). On some engines there is a module that modulates the low oil leaving the OT a solid warning to tell the operator which area is having a problem.
Drop dead scenario would be to go to the rear of the powerhead, follow the tan/lt blue stripe wire into the wiring harness that goes to the exiting plug and when you see a connection pull it apart. If the horn quits it OT, if it doesn't its low oil or your magnet fell off in your oil tank sort of thing.

 

[lgaytan]

Thanks, the oil reservoir sensor just reads level right? it will not read flow?

 

[Ifishmuskie2]

My 115 mariner has a connection block where the high temp wire and low oil wires (reads low oil only not flow)are connected together (lower starboard on engine block) and then a wire into the wiring harness up to the dash.
My alarm was going off steady so I disconnected the low oil warning and the alarm is not going off anymore.
I then put a note on the dash that the low oil warning is disconnected.
If I fill the oil every time I fill the gas it will not run out of oil.
Hopefully the high temp sensor is working. I’m not pulling the sensor and putting it in water to check.
Maybe one day I’ll fix the in tank sensor for low oil.

 

[lgaytan]

My 115 mariner has a connection block where the high temp wire and low oil wires (reads low oil only not flow)are connected together (lower starboard on engine block) and then a wire into the wiring harness up to the dash.
My alarm was going off steady so I disconnected the low oil warning and the alarm is not going off anymore.
I then put a note on the dash that the low oil warning is disconnected.
If I fill the oil every time I fill the gas it will not run out of oil.
Hopefully the high temp sensor is working. I’m not pulling the sensor and putting it in water to check.
Maybe one day I’ll fix the in tank sensor for low oil.

If what is triggering the alarm is this sensor I will disconnect it as well, that is one more reason of my doubts about this oil mixing system.

 

[Ifishmuskie2]

My oil injection system seams to be very good. Very little smoke. Quick silver oil.
Part of the reason I have a side console boat is so the windshield and Bimini doesn’t trap exhaust. My tank is about 12” tall and holds 5.3l. I did a 30mile trip and I used about 1.25” of oil. A big day of fishing I might go 60 miles. I might use 3” of oil max in a day so no worries there.
It would be nice to have a sight window in the cowl as it’s pretty heavy.

 

[lgaytan]

I think the system works but it needs maintenance, if now the sensor is bad I would need either to fix that, change the reservoir or run with the sensor disabled, in the last scenario then I will have to think and remember about oil level anyways I still need to find out what exactly is what is happening there.
By premixing in my other outboards I never had to think about this.

 

[Ifishmuskie2]

One of the reasons I want to keep my oil injection is because it does a different mix ratio for different rpm.

 

[Texasmark]

One of the reasons I want to keep my oil injection is because it does a different mix ratio for different rpm.

Well it does go from about 80:1 to 50:1 as RPMs increase but after changing my 90 HP and using Pennzoil Premium 2 stroke oil TC-W3 (Two Cycle water craft, 3rd iteration), I didn't notice any smoke including any lingering after the hole shot and looking back to see if there was any smoke.

Iterating what I said somewhere before. When I quit boating the second time (recently) I was only going out like every 3 months or so. With that lack of usage it took time to get the fuel up to the combustion chamber.....well the whole time the engine was waiting for the "bang" part of the fuel mix it was pumping oil with no gas! With pre-mix I don't have that problem.

 

[flyingscott]

Those are notorious for the tank sensor going bad.

 

[lgaytan]

Confirmed, it is the temperature sensor, it only happens when we run it at more RPMs for a while I think maybe the impeller is bad, if a rev it up the alarm goes off, I think at higher RPMs the water flow increases and cools down the motor, I will change the impeller and try

 

[Texasmark]

Those are notorious for the tank sensor going bad.

I think Faztbullet nailed it in that the magnet on the float falls off over time so you never get the signal that there is oil in the tank...but as I mentioned before a lot of engines have a modulator for oil vs a steady horn for OT.

As I read the repair methodology, its not an easy fix to get it stuck back on.

 

[lgaytan]

I confirmed in my case it is temperature issue, the alarm is not always on it goes on when on low RPMs for a while, when it happened I disconnected both sensors one at a time and it went off when I disconnected the temperature sensor. I will be changing the impeller and see how it works.

 

[Texasmark]

I confirmed in my case it is temperature issue, the alarm is not always on it goes on when on low RPMs for a while, when it happened I disconnected both sensors one at a time and it went off when I disconnected the temperature sensor. I will be changing the impeller and see how it works.

On the rear of the powerhead, upper left corner is a cap about 3" long. Under the larger diameter part of it is the Pop-off valve that opens under water pressure starting at around 2500 RPM. If it sticks closed you get a OT alarm at planing speeds.
Under the smaller diameter of the cap is the thermostat that (on my engines} was 142F as I recall...somewhere around there. If you get an OT alarm while the engine is running and you haven't reached the 2500 RPM value the thermostat is stuck shut or as you said you are investigating, the water pump isn't pumping enough water.

One way you can verify if its the pump (impeller worn out) is if the alarm sounds while traversing the no wake zone and up on plane at a decent speed.

 

[racerone]

A new impeller every 5 years.

 

[lgaytan]

Thanks for the advise I will look into all that need weekend

 

[Texasmark]

My 115 mariner has a connection block where the high temp wire and low oil wires (reads low oil only not flow)are connected together (lower starboard on engine block) and then a wire into the wiring harness up to the dash.
My alarm was going off steady so I disconnected the low oil warning and the alarm is not going off anymore.
I then put a note on the dash that the low oil warning is disconnected.
If I fill the oil every time I fill the gas it will not run out of oil.
Hopefully the high temp sensor is working. I’m not pulling the sensor and putting it in water to check.
Maybe one day I’ll fix the in tank sensor for low oil.

I had a similar fix for the same problem. When I read Faztbullets comments on here on how to get at the float and reglue the magnet on, I said !@#$% with that.....just refill the tank after every outing.