2021 SX190 - overheat warning but reality seems unlikely - suggestions?

[boldboater]

Hi, have had read a couple of related posts, but thought I would share this specific experience and see what folks think/suggest.

Just bought a 2021 SX190 with 25 hours. Great condition with exception of more scratches, scrapes, gouges in the keel than you would likely expect for the few hours... Otherwise, inside and out great condition, engine super clean.

Our trip to the gulf meandered through a series of canals at no-wake speed for 45 minutes to an hour (we were not in a big hurry, and needed to get some feel for the jet boat steering. When we got to the open water, ran it up to about 30 mph. Fine for about 3 minutes or so. Got the overheat warning and it dropped down to the limp mode at around 6-7 mph. Strong and steady stream out the side hole, barely warm to touch. We had not been in any real low or grassy/weedy areas, but checked the cleanout and found nothing. Made it to the flats and was able to swim under the boat to look at the intake and nothing of concern there - clean. When we stopped and opened the engine cover, did not have a thermometer, but temp did not seem excessive, no oil spray, not water in the compartment, etc. Load of the boat was 5 lean-to-normal adults and one teenager (maybe 1100 pounds max with coolers, etc.) - full tank of gas.

We left the flats several hours later, ran the boat up to about 30 mph and after about 3 - 5 minutes, same result. Heat warning and dropped to limp speed. Could not quickly figure out of there was a way for an owner to read any error/warning codes? After reading some posts, leaning toward the thermostat or temp sensor. The sensor seems less likely as they generally fail to 0 or infinite, and would not usually act intermittently...

Loong post - but welcome and appreciate any thoughts, ideas, suggestions!!! Obviously would love to avoid a trip to a service center - out of warranty. The ex-owner says he never experienced this, but had not had the boat out since last September (it was garaged). His use was almost all freshwater. Thanks!

 

[anmut]

Look for kinks in your cooling hose? That's what it sounds like to me...

 

[boldboater]

Look for kinks in your cooling hose? That's what it sounds like to me...

Thanks, Anmut - will look again closely, but did not notice anything yesterday...

 

[anmut]

I know some guys have had issues with the hoses collapsing due to pressure during WOT - you can keep the engine bay open while running and look for an issue if you need to (and have someone worthwhile to help).

 

[boldboater]

Well, that is interesting and not something I ever would have thought of... What would be the fix - these hoses are pretty new (2021 boat with ~25 hours). Is there an option for stiffer/reinforced hoses?

 

[anmut]

If I remember right they were just replaced with more OEM hosing and it resolved the issue. It was pretty apparent when running the boat at high speed.

 

[Marvin willis]

Oil level? Faulty temp sensor?

 

[tdonoughue]

I am inclined to suspect the temp sensor. But the fact that it is happening only when you go to WOT is suspicious.... Best idea I have heard in this situation is an IR thermometer. Not sure how much a temp sensor is (I believe there are 2 on each engine), but might not be bad to pick one up as a spare and swap it around--see if it happens again.

 

[boldboater]

Oil level? Faulty temp sensor?

Hey, thanks... Oil level is good - checked before went out and once engine cooled and sat a bit once we got out. Going to try to figure out exactly where the temp sensor(s) are and see if can be tested (ones I am familiar with are resister-type, and usually fail all the way one way or the other (open or shorted). But, these might be something different. Will check for availability and buy 1(?) to try...

 

[boldboater]

I am inclined to suspect the temp sensor. But the fact that it is happening only when you go to WOT is suspicious.... Best idea I have heard in this situation is an IR thermometer. Not sure how much a temp sensor is (I believe there are 2 on each engine), but might not be bad to pick one up as a spare and swap it around--see if it happens again.

Thanks - yes, asking around to see if I can find anyone that has an IR thermometer handy. I do see them on Amazon (of course) for as low as about $20... Do you happen to know the setpoint for the high temp warning? Figured I would ask, but will walk down and get the manual in a bit to see if it is in there...

 

[tdonoughue]

Thanks - yes, asking around to see if I can find anyone that has an IR thermometer handy. I do see them on Amazon (of course) for as low as about $20... Do you happen to know the setpoint for the high temp warning? Figured I would ask, but will walk down and get the manual in a bit to see if it is in there...

Ooh. I have seen that info on here somewhere, but I don't recall it. But it is on a thread around here...

There is also a test for them (per your other post). Pulling them has the extra benefit of getting to see what is behind them (sometimes there is scale buildup in the engine, so you can see a sample when you pull the sensor). Given the age of your engine, I don't suspect there is much buildup there or anything. But then again, given the age of your engines, I am a little surprised you are having overheating issues...

 

[VitaminSea]

This is from the service manual for my 2016 VX Cruiser HO with the 1.8L engine. I believe the same as what’s in your 190.



Bottom right of 7-15 is the thermo switch

Right column on the second page is the thermo sensor.

 

[VitaminSea]

But then again, given the age of your engines, I am a little surprised you are having overheating issues...

OP mentioned the keel was scrapped up. Wonder if the PO ran in skinny water and sand/muck was ingested. As you mentioned pulling the sensors and anode might help with seeing inside a bit. Hope it’s just one of the sensors.

 

[tdonoughue]

Very good point.

@boldboater , also, what part of the country are you in? You mentioned the Gulf. It may be that the previous owner also did not run it in as much freshwater as he said... and didn't flush (or didn't use Salt Away, etc.).

 

[boldboater]

This is from the service manual for my 2016 VX Cruiser HO with the 1.8L engine. I believe the same as what’s in your 190.

View attachment 199401

Bottom right of 7-15 is the thermo switch

Right column on the second page is the thermo sensor.

Ah. Thank you!

 

[boldboater]

Very good point.

@boldboater , also, what part of the country are you in? You mentioned the Gulf. It may be that the previous owner also did not run it in as much freshwater as he said... and didn't flush (or didn't use Salt Away, etc.).

Hernando Beach, Florida - about 40 - 45 miles north of Clearwater. The previous owner was in the Tarpon Springs/Trinity area - roughly half way between me and Clearwater. Lake Tarpon (good size lake) is just a few miles from them. Tarpon Springs and access to the gulf, but with 2 small children, believable not much time in the saltwater. Trailer does not look to have been exposed to much salt water, based on leaf springs and other non-galv parts - but, there are SOME salt indicators around the interior of the boat. So, probably not cleaned as well as I would expect to do.

 

[boldboater]

Ah. Thank you!

I see at the bottom of what I guess is page 7-16, it looks like it starts another check on the "Engine Temperature Sensor" - could you send a pic of that as well (page 7-17)?? Thanks!

 

[VitaminSea]

On my IPad, this morning, so a different layout. Here is the page you inquired about.

Maybe I’ll bump into you one day on the flats. My folks keep their boat out at HB Marina. Been meaning to take the ski out that way. Are you familiar with the ramp at Jenkins creek? Really want to avoid launching at HB if possible, and Bayport is just too far from HB and has limited parking. Was wondering with tides how shallow the canal at Jenkins gets, and during high tide, what the clearance is under the pedestrian bridge.

 

[knoxboatin]

I’ve had overheat warnings multiple times with two different conditions. Neither had anything to do with overheat. Just a few weeks ago, I had it when I ran the boat out of the marina (engines cold) with the clean-out covers not properly seated. The other situation is in my dual battery setup, if I drive the boat using the battery that does not have the full time auto bilge wire also connected to it, I’ll get it after about 10 min. Overheat seems to be the favorite error from my 2021 AR210. I’d also suggest pulling the battery and giving it a strong full charge from a quality charging unit and either getting it tested or replacing it. Don‘t count on it being an accurate error message. Sucks with a fairly new boat, good luck getting it sorted out.

 

[HawaiiBreeze]

Ok. You are not alone. I have a 2017 SX190 with the same symptoms. My own over heat conditions usually happen about 25 minutes after the boat has been started and we are under way. I have been on a quest to solve the issue and it has been elusive. To begin with I don't believe there is a crushed or weak hose that is preventing adequate cooling water (but I will keep this in mind). The evidence for this is that the engine is by passing water properly and it's not steaming or overly hot when Limp Mode arrives. The dual battery scenario above intrigues me as my 2nd battery was on its way out and bad voltage has a way of triggering all kinds of sensor issues. By the way if the late model 190s' do not have a volt meter or it's buried deep in a menu, you might consider buying an aftermarket unit and installing it. Having installed a volt meter has saved my butt twice and it's a super easy DIY.

Moving on though:

I've pulled the T-Stat and found it stuck "Open" and it was replaced. Additionally I have pulled the "Thermoswitch" and bench tested it per the Manual and it tested correctly. This switch, per the Manual is what is supposed to trigger the Overheat condition. To be on the safe side I replaced it anyway. Next I removed and replaced 1 of the "Engine Temperature Sensors" there are at least 2 of these. It also bench tested correctly but it showed rust and corrosion where the electrical leads were attached. Since the replacing these sensors I have not had the overheat alarm. However, I have not been underway for more than 25 minutes since my destinations during the winter have only been to the sandbar and back. I posted the volt meter vid and the T-Stat change on YT (links below) and the other vids for the sensor changes are in the editing stage.

Good Luck on sorting this out and post back anything that you uncover.

T-Stat Replacement Link -

Volt Meter Link -