df115 2006 overheat alarm

[kiwiflya]

I forgot to add, you might have a salt build up in the cyl head or the pressure valve in the leg is stuck open not keeping water pressure up in the engine.

pressure valve removed and checked, seems to spring as it should.

[kiwiflya]

I was getting a random overheat alarm as well. I used my infrared and couldn't find anything on my engine that appeared to be running too hot. I have my DF140 networked with my Lowrance, and the temp wasn't showing hot either. There are 2 temp sensors, one on top close to the thermostat, and one on the rectifier. I disconnected the one up top, and still got the alarm. I then disconnected the one on the rectifier, and the alarm went away. I replaced that sensor. I do not have enough hours on the motor since replacing the sensor to know for certain it was the issue (since it was just a random occurrence), but I am guessing I am right.
-Shawn

Yes i had a similar issue on an older 4 stroke outboard and i am now thinking the same thing even if the beep code indicates voltage. (the light on dash indicates temp). The nature of these thermistor style temp sensors is fickle with fluctuations. The exhaust manifold sensor will always fluctuate quicker than the cylinder sensor so this could be the problem i guess. I believe the later models only have a single cylinder head sensor.
Ok im going to pop a bolt in the hole and let the thing dangle the exhaust manifold. From what i learned it is that Voltage can spike and return a signal back to the cpu that is out of bounds and hence isnt logged and shutdown ensues. Wish me luck, get back to you all soon.

[kiwiflya]

If you remove the connector from either the cyl temp sensor or the exhaust manifold sensor it will automatically log a code, and the check engine light flashing a 1.5 or a 1.4 code. With the key on the buzzer will buzz the code, What you say when you disconnected the exhaust manifold sensor plug the buzzer went away, it should have flashed a 1.5 code with the buzzer.

Yes get the standard flashes and aural alarms if remove the sensor whilst running. The buzz code i get with my problem is a 1-1-1-1 at about 5-6 second interval . Not sure if I understand the comment you posted though.

[redlowrey]

Yes get the standard flashes and aural alarms if remove the sensor whilst running. The buzz code i get with my problem is a 1-1-1-1 at about 5-6 second interval . Not sure if I understand the comment you posted though.

Sorry mate that was meant for WEDOCQ, hook the motor up to the muffs and connect a digital multimeter up to the signal line on either sensor and watch the voltage change as it heats up. Depending on temperature the voltage will range between 4.5 volts cold engine to 0.10 hot engine, you might see the voltage go erratic at a certain temperature and the temp light come on.

[kiwiflya]

Sorry mate that was meant for WEDOCQ, hook the motor up to the muffs and connect a digital multimeter up to the signal line on either sensor and watch the voltage change as it heats up. Depending on temperature the voltage will range between 4.5 volts cold engine to 0.10 hot engine, you might see the voltage go erratic at a certain temperature and the temp light come on.

Good idea. I cant seem to get the thing to alarm on the muffs. I have removed the sensor from the exhaust manifold for the time being as i see the newer models dont bother with a sensor there.
Havent been out in the boat yet to test it. Anyone know if water should come out of the exhaust manifold temp sensor hole?

[redlowrey]

Early engines sender will sit in water late engine blind hole, just have a look when you take the sender out.

[kiwiflya]

Early engines sender will sit in water late engine blind hole, just have a look when you take the sender out.

Cheers i put a 8mm bolt with gasket on just in case. Fingers crossed for when i get out on the water again.

[kiwiflya]

problem solved

It turns out that I had the idle too low. It would idle at 100 plus degrees C.
Tweaking the idle up 100 or so rpm give enough flow to keep the temp at around 60 to 70 degrees. All this was made possible through monitoring the motor through an engine interface and lowrance fish finder display.