Resintance Reference Needed for Temperature Sensor (34830-87JA0) EvinSUki DF50 1999

[pandilucciano]

Hi, I have a 50 HP Evinrude 4T 1999 outboard engine, the so called EvinSuki engines, and its been sending a "HOT" alarm after runing at 5900 rpm and throttling down when approaching destination. Its not when at full speed, its when I go down to 2000 rpm, it will shoot out the alarm.
Impeller has been changed, and water jet its coming out normal (i'm missig to meassure water temperature coming out), a bit hot dot not scalding at all.
I decided to open the engine and see for the internal lines to see if it had any scaling, it looks good (see picture below), so I decided to go for the water Sensor.
I took it out and performed a series of reading son different water temperatures (digital accurate thermometer) and a ohmeter to read the resistance.
I'm wondering if anyone has the reference of readings of temperature vs resistance for this particular sensor so I can compare and see if sensor might be off.... Below my readings THANK YOU!

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[Moonlighter]

Cant help with the resistance readings....

Anyway, did you do a FULL water pump kit when you changed the impeller? Its always a good idea, there have been many reports where the old plate/housing may be slightly out of shape (many not be easily visible to the naked eye) and this affects impeller performance. So if not done, I would suggest you do the full kit replacement.

[tsturm]

How is the thermostat? Sticking possibly?

[pandilucciano]

Cant help with the resistance readings....

Anyway, did you do a FULL water pump kit when you changed the impeller? Its always a good idea, there have been many reports where the old plate/housing may be slightly out of shape (many not be easily visible to the naked eye) and this affects impeller performance. So if not done, I would suggest you do the full kit replacement.

Thanks, no I didn't do the full, we have removed the thermostat as they placed a suzuki 60hp thermostat, and i think it runs at 60C instead of 50C... By the way whats the running temp of eater in these engines?
so I will check tomorrow to see if that has something to do....

[pandilucciano]

How is the thermostat? Sticking possibly?

We removed it now, mechanic had put a suzuki 60 ho thermistat which apparently runs at 60C instead of 50C...
in the case that you suggest, how would that work??

one more, whats the running temp of water in these engines?
Thanks

[pandilucciano]

Cant help with the resistance readings....

Anyway, did you do a FULL water pump kit when you changed the impeller? Its always a good idea, there have been many reports where the old plate/housing may be slightly out of shape (many not be easily visible to the naked eye) and this affects impeller performance. So if not done, I would suggest you do the full kit replacement.

Also found these in the online manual...

[Murray]

DD735CCB-4401-4C81-A6E5-3CB0F212E8A4.png


From a 2009DF-90A. Looking at your graph and comparing it to my service manual data it appears that your values aren’t out of line. So your temperature sensor appears to be operating properly. Moonlighter post is worth considering, here’s a theory, running at 5900RPM adequate volume of cooling water, cut RPM’s to 2000 RPM and the impeller is pumping some water but not quite enough hence the overheating alarm. The telltale water is ejected out before it circulates through the engine so the telltale water will not be at engine temperature. The telltale only function is to verify that the impeller is spinning. For the price of a complete water pump kit I’d start there. When installing the impeller use soap or grease to pre lube the rubber/steel interface and ensure the vanes of the impeller are turned the correct way. If memory serves the driveshaft is turned clockwise to seat the impeller. VERIFY my last sentence.

[pandilucciano]

DD735CCB-4401-4C81-A6E5-3CB0F212E8A4.png


From a 2009DF-90A. Looking at your graph and comparing it to my service manual data it appears that your values aren’t out of line. So your temperature sensor appears to be operating properly. Moonlighter post is worth considering, here’s a theory, running at 5900RPM adequate volume of cooling water, cut RPM’s to 2000 RPM and the impeller is pumping some water but not quite enough hence the overheating alarm. The telltale water is ejected out before it circulates through the engine so the telltale water will not be at engine temperature. The telltale only function is to verify that the impeller is spinning. For the price of a complete water pump kit I’d start there. When installing the impeller use soap or grease to pre lube the rubber/steel interface and ensure the vanes of the impeller are turned the correct way. If memory serves the driveshaft is turned clockwise to seat the impeller. VERIFY my last sentence.

Thank you! Yes, they are ok!
so I went out today, we removed the thermostat, no problem at all during all day, after running I stopped and opened the cover and checked the head temperature right around the 2 sensors (head and water, by the way both are the same sensor) an i got readings of 61°C, obviously temperature profile is not the same across the dead cross sectional area, but seems ok.
I cheched with a digital thermometer on the water coming out, and it was coming at 31°C.
So as you say, for the price of a pump case Ill go ahead and change it, thanks for the tips.