Mariner Motor Heat Sensor

[the doctor]

for all you mechanically inclined:

went fishing Sat and early in the trip the heat sensor started buzzing from my throttle controls

motor was using oil from the reservoir and water was flushing through, also the motor perfomred fine the rest of the day except for the constant beeping

now the motor has rested for two days and when I turn the key as if I was to crank it the beeping starts again

I think I may have a bad sensor, but looking for some input, am I missing something? How hard is it to replace this sensor? $$$??

the doc

[stumpjumper]

I always cut the wires and bypass the sensor.I have had two motors go bad because of them not mixing the oil. I just prefer to mix the oil myself and know the oil is in there.

[JMallard]

my experience with a Mariner....if you will loosen those bolts/screws that are holding it to your transom and let it fall into the deep part of the river your life will be better off.

[MudHog]

my experience with a Mariner....if you will loosen those bolts/screws that are holding it to your transom and let it fall into the deep part of the river your life will be better off.

This reminds me of how to cook a jack cravell.


Mariners are still some decent motors. If the sensor is giving you trouble, start mixing your own oil. Mix it like you do any other 2 stroke outboard. Just pour the oil down your fuel filler. Got a buddy with a 21' Robalo and a 225 Mariner. Mixes his own oil every time he puts fuel in the boat.

[the doctor]

did a little exploratory tinkering this afternoon

definitely the sensor and/or oil pump... the wire leading from there was the source of the problem

so dont know if the sensor is bad or the pump is bad

the motor was using oil, but maybe not like it should and the alarm keeps sounding event hough the motor hasnt run in two days

will the alarm sound if the pump is bad even though the motor isnt running or hasnt run?

makes me think it is just a bad sensor????

need help

the doc

[sondance]

I used to have an offshore boat with twin Merc's (same thing). My warning buzzer went off and all it was , was a smaill crap in the filler cap on the oil res. No pressure so it was not getting enough oil. Scraed the @#$% outta me considering we were 70-80 S of Biloxi at the time

[oldriverhunter]

That motor doesn"t have a flow sensor on the oil line. It has a oil level sensor to let you know that you are running low on oil. Sounds like you have a bad heat sensor. Try this unplug your overheat sensor (there will be one on each head) then turn your key on. Do this on at a time. Turn the key on each time, when the alarm doesn"t sound you have found the problem. Then once you have found the sensor take a volt ohm meter and check it. It will show open if the sensor is good, you will get a reading if it is bad. Do this just to make sure that you don"t have a wiring/harness issue. Good luck let us know how it turns out.

[Caller1]

I bet Lenny and Lesley could fix it!!!! Muahahah

Doc, doesn't Torch's Auto do some motor work?? May want to ax him!