Flashed SHO temperature

[Taylor]

I have a 2017 SHO that’s been flashed by hydrotech but kept the stock rev limiter. The engine is connected to my Lowrance and most of the time, I see 145 degrees which is similar to what most people seem to run. However on long WOT runs (>5 mins at WOT) Temps start creeping up to 160-170 and sometimes close to 180. Typically I run 15 psi at WOT. Water pump is brand new (was doing the same with old water pump). I cleaned the thermostats and flushed water through all the lines, but am still having the same temps. Curious if anyone has seen similar or has ideas on what else to check. Also for those with flashed ECUs, what temps do you see at WOT?

[SCOTT196]

Ask Mat at Hydrotech.

[yam911]

The temperature indication seen from an SHO via the Yamaha Command Link network and on to an NMEA 2000 display has little to do with water temperature. It is the temperature of the block that is being measured.

The over temperature alarm point for the block is 302* F. You are a long, long way from the block over heating. I don't see a problem.

[CJ1]

^^^^^ good info to know CJ

[Bryan S]

I wish mine hit 180 degrees to help seat the rings

[kry29]

I wish mine hit 180 degrees to help seat the rings

That's what I was really thinking.

[Quantum]

Done some work on this recently. Your Lowrance temperature is not “real”, it’s a calculation based on ECU factors combined with the sensor on the block (not water temp). So at 5900 the block will be around 250 degrees and the ECU will assume the water temp will be X and send that to the Lowrance.

You haven’t hit 302 at the block as that would trigger a SLOW mode alarm. But what you should try and do is have the YDIS plugged in after a hard 13 mins running and see your actual block temps and how close to 302 you are getting. Then you can decide if it’s something you want to worry about.

[yam911]

Done some work on this recently. Your Lowrance temperature is not “real”, it’s a calculation based on ECU factors combined with the sensor on the block (not water temp). So at 5900 the block will be around 250 degrees and the ECU will assume the water temp will be X and send that to the Lowrance.

You haven’t hit 302 at the block as that would trigger a SLOW mode alarm. But what you should try and do is have the YDIS plugged in after a hard 13 mins running and see your actual block temps and how close to 302 you are getting. Then you can decide if it’s something you want to worry about.

Where did you get this information?

[Taylor]

Done some work on this recently. Your Lowrance temperature is not “real”, it’s a calculation based on ECU factors combined with the sensor on the block (not water temp). So at 5900 the block will be around 250 degrees and the ECU will assume the water temp will be X and send that to the Lowrance.

You haven’t hit 302 at the block as that would trigger a SLOW mode alarm. But what you should try and do is have the YDIS plugged in after a hard 13 mins running and see your actual block temps and how close to 302 you are getting. Then you can decide if it’s something you want to worry about.

What do you need for the YDIS plug in?

[Quantum]

Thats a dealer job unfortunately. You don't have to do it on the day - the dealer should be able to see the last 13 minutes of run time.

[Quantum]

Where did you get this information?

A heap of reading and phoning around trying to understand how NMEA temp is generated given the SHO only has one true temperature sensor and the range on that is far wider than ever seen on NMEA. In normal running that sensor is reading the metal block (not water) 0 to 250F. Your NMEA is showing 0 to 145F but its not a linear relationship. At idle your block is around 140 and our NMEA will show the same. At WOT your block is around 250F and your NMEA will show 145 maybe.

Truth is no-one outside of Yamaha really knows 100% how it works but NMEA is not the most reliable way to monitor temperature on an SHO.

[yam911]

A temperature sensor (negative co-efficient variable resistor) is used to measure block temperature. Up near the top of the block.

At room temperature the sensor has X resistance. As the block (and the sensor) heat up the resistance of the sensor goes down. As the block (and the sensor) cool down the resistance goes up.

The ECU sees the varying resistance values as temperatures. As follows:

4.2K ~ 4.9K Ohms = 41* F.
1.9K ~ 2.1K ohms = 77* F.
0.166K ~ 0.204K ohms = 212* F.

Temperature is output by the ECU to generally a Command Link display. It can also be provided to an NMEA 2000 device as well. I would expect the NMEA 2000 display to be reporting actual temperatures as seen by the sensor.

Would be interesting for someone with a SHO and an NMEA 2000 device to put the temperature sensor in water and monitor what the display is showing as the water temperature varies.

[Triton19x2]

Hydrotech says they see these temps often in their dyno tests and they told me that at 192 the motor would go into guardian mode.

[yam911]

Hydrotech says they see these temps often in their dyno tests and they told me that at 192 the motor would go into guardian mode.

Yamaha says 302* F.

[Taylor]

Does anyone know where the oil cooler is on the SHO? I can’t find it in the parts schematics but saw reference to a potential oil cooler problem with high block temps. I ended up shaving the back of my water intake screens to get them to sit flush and drilled some larger holes angled to the water flow. I gained a couple psi (now 17 lbs at WOT). Haven’t had a chance to run it long at WOT but believe I saw temps creeping above 150 again. Want to check that the oil cooler coolant lines are not plugged

[yam911]

[FOURCED]

Another View

https://www.ebay.com/itm/yamaha-outb...kAAOSwopRYgnCx

[Quantum]

Yamaha says 302* F.

That 302F is taken from the block sensor. There is a thermo switch on the each head that will trigger around 185 to 192 creating the same alarm and rpm limitation.

[Quantum]

Does anyone know where the oil cooler is on the SHO? I can’t find it in the parts schematics but saw reference to a potential oil cooler problem with high block temps. I ended up shaving the back of my water intake screens to get them to sit flush and drilled some larger holes angled to the water flow. I gained a couple psi (now 17 lbs at WOT). Haven’t had a chance to run it long at WOT but believe I saw temps creeping above 150 again. Want to check that the oil cooler coolant lines are not plugged

What hp was your flash from and to?

[Taylor]

300 stock rev limiter, Hydrotech flash