Overheating Warning - Temp Sensor Questions

[WREKS]

That is the cooling water outlet coming from Exhaust 2 on my 2007SX230HO. As @Scottintexas said, it appears that it was not used on the 2006SX210. Also, the horizontally placed hole at the top of your pictures is the exit for the cooling water going through the thermostat. If you are running on the hose and water is not streaming out of that hole after idling for several minutes, the thermostat probably has to be replaced.

 

[buckbuck]

I concur. The engine you have will have those holes blocked off from the factory. Do the @CrankyGypsy closed loop flush that @Scottintexas recommended.

 

[Canuckjetboater]

Thanks for the reply @Mainah! I have done all the service on it so far and 450 HRs later thankfully I have yet to need a service manual “knock on wood”

I’m having a hard time finding much detail on the sensors and/or a diagram of the system. If anybody has a pdf of the service manual for a 2013 SX210 please shoot me a PM.

@Bacchus_fl .......new to jet boats but on my go fasts and cruisers with twin engines the heat sensors were easy to swap as they were plug in/out. IF this is the case could you swap them side to side to see if the suspect one is faulty? I have done this with several sensors on I/O engines to find the culprit.

 

[CrankyGypsy]

If you can confirm there is no hose kinking happening or sensor failure with the YDS, take Scott's advice and do my closed-loop flush. Especially since vinegar and Dawn dislodged larger crud - I tried a few of these weaker options, but they did practically nothing to cure my overheat issue. I'd go so far to recommend doing my flush every 1-2 seasons if in salt water: I think I did 3 flushes in 12months and was still getting a surprising amount of fine calcium out. If the boat was not adequately flushed by the previous owner as my was, the calcium build-up becomes a ceramic coating that prevents heat from leaving the system, thus tripping the sensors. The water out of both pissers might feel the same at exit, but part of the engine might be retaining heat.

Via the YDS, a bad sensor will likely operate correctly until a certain threshold. At that point, it will suddenly and drastically jump inside overheat range every time - if you keep a close eye, you'll see it occur in real time on the laptop. I also used an infrared thermometer to compare areas of one engine to the other to confirm. I found a lot of heat can build up at the front cylinder because the flush enters the back of it. If there's thick blockage around the front cylinder, it will take several closed-loop flushes to slowly eat it away. The more pressure you can get in to allow higher flow current through the system (this is done by opening up the exhaust exit - don't shortcut my instructions), the better the process works.

 

[Mcaro012]

Did replacing the thermosensor work? What was the final outcome? I'm worried my AR210 overheating has a blown head gasket because it overheats unless it's just a bad sensor that says it's overheating.

 

[WREKS]

@Mcaro012 Taking temp readings on the exhaust side along cylinder block while running on the hose is a good way to diagnose overheating. Temperatures in the 200F range will signal an overheat. The cylinder water jackets may be clogged.