over heat issue , can we run our 1.8s without a thermostat ?

[yam240sx]

have some over heat issues was thinking about pulling the thermostats and running without them .. temporarily of course ... thanks

 

[yam240sx]

is addition had few other questions to anyone whos has knowledge on the topic .... since my star engine was over heating actually both pissers were flowing just fine pressure wise except both were flowing cold .. not piss warm like they should be and both engines were running hot ... so where was this cold water coming from ? not cooling engines ? thanks

 

[SDAnderson51]

have some over heat issues was thinking about pulling the thermostats and running without them .. temporarily of course ... thanks

If you are doing it as a troubleshooting tool under controlled conditions I might try it, although I would not do it. I know it is not exactly the same in auto engines, however they serve a vital purpose and running without them can lead to significant unexpected consequences.

 

[Ronnie]

I have a feeling that running without a thermo would trigger the engine to go into safe mode (limit the rpms such that you won’t be able to get in plane) which is a good thing if the alternative is destroying your engine. Personally I would price out what an engine costs and then take mine to the dealership or shop and pay them to at least determine the cause of the warning.

 

[TimW451]

@yam240sx If the engines are overheating (vs false temp sensor) and the water coming out the pissers is cool, it sounds like you have a circulation problem in the engine cooling passages. I’d search on similar topics here, but I believe some disassembly would be in order. But definitely verify the condition first, check temp sensors, put an infrared thermometer on the engine/exhaust Before taking things apart.

 

[boldboater]

is addition had few other questions to anyone whos has knowledge on the topic .... since my star engine was over heating actually both pissers were flowing just fine pressure wise except both were flowing cold .. not piss warm like they should be and both engines were running hot ... so where was this cold water coming from ? not cooling engines ? thanks

I have been working on an unusual overheat warning on my 2021 SX190 (thread in here) - after exhaustively looking at diagrams and the boat hoses/connections, I am confident in saying the pissers indicate cooling water is coming in and getting as far as the oil cooler (first major engine component the water gest to). The pisser hose actually comes off the oil cooler - not further back where the water has actually been through the engine. My problem is not fully resolved yet, might have been a sticking thermostat as the new one seems full open at about 140F while the old one started at about 140F and was full open nearer 180F. Can determine if good flow all the way through the engines by removing the thermostat and running the engine (not in the water, on land with the flush connected) to see if you have water coming out the end of the cooling loop past the thermometer - the water dumps from an exit right on top of the jet from the top of an indent in the hull. On the SX190, just to the right of impeller center line and above it.

 

[HawaiiBreeze]

I can answer this from practical experience and the answer is "Yes". I had an overheat issue too so I went to the T-Stat and found out that it was locked "open" and for how long I have no idea. It has since been replaced and before installing it I tested it on the stove. It worked as indicated. Besides pump/debris/sand clogging issues the overheat problem can be coming from the Thermo Sensor which is supposed to be the trigger for the Overheat Alarm-Go Into Limp Mode and there are two or three other sensors on the block that are heat related. I've replaced the Thermo-sensor and 1 of the others. If you pull them off you can bench test them on the stove too. Both of mine showed to be in working order but that's the rub, the boat runs fine, the alarm goes off, boat goes limp mode and 3 minutes later its running like nothing ever happened.

 

[yam240sx]

so alarm starts as soon as engine is fired up , after running for 10-15 in on hose i do not get warm water coming out the pissers , its just cool / cold .. why is that ? what is causing that ? all from a sensor ? i pulled and checked both thermostats and they are clean and good working order , i replaced back and also get good hot flow out the back above the transom plate so this is not the T stats , but the pissers are cool and cold with good pressure and alarm will not stop, also will yds show me if one of these sensors was bad ?

 

[yam240sx]

i hit the silent button just to shut off the beep but the over heat alarm is still flashing

 

[VitaminSea]

so alarm starts as soon as engine is fired up , after running for 10-15 in on hose i do not get warm water coming out the pissers , its just cool / cold .. why is that ? what is causing that ? all from a sensor ? i pulled and checked both thermostats and they are clean and good working order , i replaced back and also get good hot flow out the back above the transom plate so this is not the T stats , but the pissers are cool and cold with good pressure and alarm will not stop, also will yds show me if one of these sensors was bad ?

If the alarm is starting as soon as you fire up, have you confirm its been cleared? Does the Candoo work like the YDS - that is the OH alarm is only recorded once until its cleared. For example, if you tripped a OH alarm at 100hrs, it cleared itself, but is still held in memory… then at 105hrs, you get another OH alarm, YDS would only have the 100hr alarm logged in memory. What I am after is, if you have cleared the alarm and its not viewable in the software, does it reappear the moment you fire back up the engine? If yes, I would think that’s one of the thermo sensors. The service manual should have some specs on how to test if the sensors are still working…

Also, with the YDS software, it will give you real time readings of temperatures from the different sensors in the engine. Are you able to see those with the Candoo, and if Yes, do any of those readings appear suspect?

In case you do not have a service manual, here is a link to a few pages from the service manual for my 2016 VX Cruiser HO with the 1.8L. Not certain if the sensors are any different on your model year.

https://jetboaters.net/threads/2021-sx190-overheat-warning-but-reality-seems-unlikely-suggestions.41069/post-647920

 

[yam240sx]

i have the service manual , just got the yds adapter and software .. havent plugged it up yet .. Just dam curious could a sensor be causing all of this ?

 

[boldboater]

so alarm starts as soon as engine is fired up , after running for 10-15 in on hose i do not get warm water coming out the pissers , its just cool / cold .. why is that ? what is causing that ? all from a sensor ? i pulled and checked both thermostats and they are clean and good working order , i replaced back and also get good hot flow out the back above the transom plate so this is not the T stats , but the pissers are cool and cold with good pressure and alarm will not stop, also will yds show me if one of these sensors was bad ?

The water from the pissers comes early in the cycle - the water has just come into the the engine bay and entered the oil cooler - the pisser flow comes where the water exits the oil cooler. Useful to show you have water coming from the jet/impeller, but not that water flows through the engine. My pisser water is always pretty cool.

 

[boldboater]

i have the service manual , just got the yds adapter and software .. havent plugged it up yet .. Just dam curious could a sensor be causing all of this ?

Do you mind sharing where you got the YDS adapter and the software??? Thanks!

 

[anmut]

The water from the pissers comes early in the cycle - the water has just come into the the engine bay and entered the oil cooler - the pisser flow comes where the water exits the oil cooler. Useful to show you have water coming from the jet/impeller, but not that water flows through the engine. My pisser water is always pretty cool.

Weird, mine is always warm after a hard run of surfing - that's just from the oil cooler and not from the block? I guess that would make sense - probably a liability to eject 160f' randomly out the side of a boat...

 

[boldboater]

Weird, mine is always warm after a hard run of surfing - that's just from the oil cooler and not from the block? I guess that would make sense - probably a liability to eject 160f' randomly out the side of a boat...

Correct - the pisser comes out of the oil cooler.


In the diagram, 15 is water inlet to oil cooler from the jet drive intake. 22 is the pisser hose. 20 is a branch off that goes to the cylinder head. So, pisser can get warm if engine is run fast/long enough, but have never seen it really hot. That would likely indicate a problem...