My brother recently bought a boat - without ever even hearing the engine run. But he has a bad case of "boat fever" and as soon as he got it, he needed to try it out. So - still without ever testing the engine or even opening up the engine cover to look around - he grabs my son and off they go to a local river for "sea trials".
Things went well at first. The engine revved right up and planed the boat - everything was great! That lasted about 10 minutes, then the engine hit the wall. It powered way down and would not respond to increased throttle. They called me for help.
I know basically zero about outboard engines and could only suggest that they let it cool off and try it again. After a cool-down period it did run better- for about 2 minutes. They gave up and eventually sputtered back to the boat ramp. They pulled it out of the water and parked it.
Yesterday I finally got a chance to look under the cover. The first thing that caught my eye was the stbd jacket water high temp cutout sensor (please excuse my terminology, I am making the names up). The threads on the mounting bushing were stripped, the rubber seal was popped out of the casting hole and the actual temperature sensor was laying against the engine casing.
Here it is on the bench:
I am assuming that because it was in contact with the hot engine casing - rather than in the coolant stream - the ECM was getting a high temp signal. Due to the high cooling water temp, the ECM powered the engine down as designed. Correct?
The threads on the bushing are completely gone and I hate to hold sensors in place with sealant. It needs to be fixed.
To make the repair, I have to cut the wire, install a new bushing and then solder & heat shrink the sensor lead anyway. So, while I had it out, I figured I would test it.
It tests open on the bench now. No matter how hot I get the sensor head (Airpax 0214), I do not get continuity. I am assuming that the limit switch is normally open and closes upon rising. Also assuming that when it closes, the ECM senses high coolant temp and reduces engine power (and completes an alarm circuit). I have tried a hot water bath (maybe up to 180F), direct contact with a light bulb and even a Weller soldering gun - I can't get the switch to close.
I tested the thermostat for that side as well. It stroked smoothly - and was fully open (I think fully open - about 3/8") by about 150F. Am I not gettting the limit switch hot enogh to close? I can't find any specs on that Airpax 0214 does anyone know the close set point?
And most importantly, are my assumptions on the operation of this circuit correct (i.e. does high jacket water temp close the switch, complete a path to ground and signal the ECM to ramp the engine power down)?
Things went well at first. The engine revved right up and planed the boat - everything was great! That lasted about 10 minutes, then the engine hit the wall. It powered way down and would not respond to increased throttle. They called me for help.
I know basically zero about outboard engines and could only suggest that they let it cool off and try it again. After a cool-down period it did run better- for about 2 minutes. They gave up and eventually sputtered back to the boat ramp. They pulled it out of the water and parked it.
Yesterday I finally got a chance to look under the cover. The first thing that caught my eye was the stbd jacket water high temp cutout sensor (please excuse my terminology, I am making the names up). The threads on the mounting bushing were stripped, the rubber seal was popped out of the casting hole and the actual temperature sensor was laying against the engine casing.
Here it is on the bench:
I am assuming that because it was in contact with the hot engine casing - rather than in the coolant stream - the ECM was getting a high temp signal. Due to the high cooling water temp, the ECM powered the engine down as designed. Correct?
The threads on the bushing are completely gone and I hate to hold sensors in place with sealant. It needs to be fixed.
To make the repair, I have to cut the wire, install a new bushing and then solder & heat shrink the sensor lead anyway. So, while I had it out, I figured I would test it.
It tests open on the bench now. No matter how hot I get the sensor head (Airpax 0214), I do not get continuity. I am assuming that the limit switch is normally open and closes upon rising. Also assuming that when it closes, the ECM senses high coolant temp and reduces engine power (and completes an alarm circuit). I have tried a hot water bath (maybe up to 180F), direct contact with a light bulb and even a Weller soldering gun - I can't get the switch to close.
I tested the thermostat for that side as well. It stroked smoothly - and was fully open (I think fully open - about 3/8") by about 150F. Am I not gettting the limit switch hot enogh to close? I can't find any specs on that Airpax 0214 does anyone know the close set point?
And most importantly, are my assumptions on the operation of this circuit correct (i.e. does high jacket water temp close the switch, complete a path to ground and signal the ECM to ramp the engine power down)?