MFD is still reading "HOT" when at WOT.. what now?

[javiert99]

I'm at a loss.

Been out 5 times since the rebuilt engine was installed. First and second time was all low throttle operation, no warnings.

Third time out I was able to take it up to 90% throttle for break in, if I would ride for continuous amounts of time at 5500 rpm or over, it would start to blink red and display HOT on the MFD. After this third time I thought I might have a clog so I flushed as usual and water flowed as normal. Just in case I inspected the water manifold rail (removed/rinsed) and checked incoming hose lines and outgoing lines, all clear and fine.

Fourth time out I was able to give it full throttle and went out to the intracoastal before doing some ocean time. Went WOT and sure enough HOT warning came on. Did a few more passes and it didn't come back on. Hrm. Spent about 2 hours on the ocean at varying throttle and it never came back on. Has run perfect.

Took it out to the canal again today and did some smooth water high speed runs and the HOT display shows up again. WTF? Checked my intake screen, it's clean and clear. I would chill for a bit, do another extended high speed run, and it would come back on. If I keep it at mid throttle operation it's fine..

Took it back home and flushed, water comes out just fine through the intake screen.

What else can I check. Could the sensor malfunction only at WOT? Could the new engine have a blocked passage? I'm so confused All my lines are routed properly.

[David3aces]

Re: MFD is still reading "HOT" when at WOT.. what now?

try a new sensor...................

[javiert99]

Re: MFD is still reading "HOT" when at WOT.. what now?

Yah, I'll try that, I imagine it's cheap enough (already spent a bundle on this thing, if I can avoid anymore I'd like to).

How about the thermostat, would that cause any problems? I thought the thermostat gets bypassed after a certain RPM anyways by the pop off valve towards the back of the water manifold, but I'm not sure.

[dank]

Re: MFD is still reading "HOT" when at WOT.. what now?

The sensor may be activating at a lower temp then needed. This will cause it to turn on the temp warning light before the pipe realy gets too hot.

Do you have two sensors on that ski or just one? I have used Polaris parts for the SL models if you need a used one.

FYI I do not have any MFD's for sale. It seams there are twenty people looking for them at any one time.

[javiert99]

Re: MFD is still reading "HOT" when at WOT.. what now?

i've only got one sensor on this one.. it's the round one that fits into the exhaust manifold with the rubber grommit.. have any pics of it? I'll probably take one off your hands after I test the thing out sometime today.

[Wet Wolf]

Re: MFD is still reading "HOT" when at WOT.. what now?

Pull the popoff valve and therm out to get max waterflow into engine and see if that makes a diff, thats the easiest thing to try 1st. if the lite still comes on, pul the sensor out of the manifold and try again. If the lite still comes on, unplug the sensor in the elec box and try again. if the lite stil comes on, you've got an electrical problem.
did you feel the manifold, was it hot?

[javiert99]

Re: MFD is still reading "HOT" when at WOT.. what now?

Hi Bruce, one of the guys at pwctoday asked me to try touching the manifold itself next time out. If I recall correctly I did, and it was warm but not burning hot. I'm going to try to go out tomorrow (or later today if the weather clears up) to see.

I'll try all you noted next time out and see what kind of results I get.

Thanks! :)

[javiert99]

Re: MFD is still reading "HOT" when at WOT.. what now?

Update, the sensor is good. From what the gents over at pwctoday have told me it's a 160* sensor. Tested the sensor by heating up to 160* in a pot and getting continuity in the signal from the wire once reached that temp (when cold it's an open circuit)

My next test will be to remove my thermostat and popoff and go for another run to see if it makes a difference after I reinstall my sensor.

Question for TS, do these motors run significantly hotter during break in than normal? Enough to trip the sensor possibly?

[javiert99]

Re: MFD is still reading "HOT" when at WOT.. what now?

Question for TS, do these motors run significantly hotter during break in than normal? Enough to trip the sensor possibly?

Any thoughts TS? As an additional note, the water I've been testing in feels signficantly warmer than when I was riding 4 weeks ago in these canals. The water is pretty much lukewarm.

[Technical Support]

Re: MFD is still reading "HOT" when at WOT.. what now?

No they do not run significantly hotter. The temp sensor is reporting on cooling water flow only. The engine doesn't heat up enought o trip it, it's only from lack of flow or a bad sensor. Get a new sensor.

[javiert99]

Re: MFD is still reading "HOT" when at WOT.. what now?

Well the sensor tested properly and it worked before... it was suggested that I place some silicon grease around the sensor so it picks up temps properly and not hotspots. Unless it's failing intermittently which would be odd. The waterflow issues I still need to check are the thermostat and popoff (ie, run the thing w/o them).

[Technical Support]

Re: MFD is still reading "HOT" when at WOT.. what now?

From what you've said, the sensor is most likely bad, even through you get apperantly good test readings. Silicone will not make a difference.

[javiert99]

Re: MFD is still reading "HOT" when at WOT.. what now?

Here's to hoping you're right! :) I'll look into ordering one I guess..

[javiert99]

Re: MFD is still reading "HOT" when at WOT.. what now?

Just an update.. it *has* to be the sensor. Took it out and rode it HARD for an hour today, with the light coming on multiple times. Taking out the popoff and thermostat didn't make a difference.


Dropped it in the canal and rode around for a while to warmup, then hit the throttle for a while. Sure enough, "hot" light starts bitchin'. I pop the seat, check my exhaust manifold, and it's maybe "warm" to the touch, but barely. Uuuuum, ok. My cylinders/head covers are pretty hot, but I can keep my hands on them for a few seconds before feeling a burn.

Run back to the ramp and remove my thermostat and popoff valve. Take it back out and run it hard. HOT light comes on.. I ignore it and ride the piss out of it for two more minutes. I figure if it's going to seize.. let it.. tired of it. Stop the ski w/ the light flashing and the exhaust manifold is now pretty much almost cool to the touch, barely even warm.

Sensor's got to be bad.. I literally touched the sensor and the exhaust manifold around it, cool/lukewarm to the touch. If that thing was really registering 160* I think the outside of that manifold would have burned my hand!

Oh well... I'm just gonna ride it how it is, enjoy it and disconnect the sensor for right now. When I get a chance I'll order one and see what that does. Maybe I'll check my electrical box to see if something is frayed or shorted out somewhat, but I doubt it.

I did put the thermostat and popoff back in. I noticed without them in and running the flush kit it seems no / hardly any water actually make it into the engine w/o them. Water just goes right through the holes and out the exhaust.