250 PRO XS 4S oil temperature

[howieranger]

Has anyone noted their oil temperature during a long WOT run. mine goes up to 256* in 65* water. I cannot find anywhere in the manual that lists upper limits for oil temperature and am wondering if this is normal. sn 2b529959

[idratherbeefishin]

Yes thats normal mine runs around 225-250 after long runs, the pressure is 60-80 psi depending on throttle . Mercury v8 4 stroke 200hp

[mikesxpress]

Don what is the oil temp supposed to be for extended runs at WOT?

I can find no information on a high oil temp alarm the Smartcraft would emit. One would think it would be "alarm capable" and what would be the temp the alarm would sound off?


250 V8 #2B529759

65 water temp, 58 air temp, 28 minute run at WOT Smartcraft showed 271 degrees oil temp toward the end of the run. Once off plane it cooled down rapidly. Water pressure was 28 psi. No issues with cooling. No alarms.

[mikesxpress]

Another oil related question.

The service manual shows an optional oil level sensor. If this were installed would it show on the level 1 merc monitor, is it alarmed, and at what oil level would it alarm?

[mikesxpress]

Don how about the oil temp?

[EuropeanAM]

Sorry guys- off on weekends.

Oil temp will vary based on a number of factors. Common to see it in the mid 250's (sometimes even higher). Each calibration has it's own specific Guardian limits, so the figures can vary from one engine model to another.

That being said- I know I've seen one well above 255 without warnings.

Oil Level Kit: This allows the Oil Level to be referenced on Smartcraft. You SHOULD be able to utilize it on the FACE of a Level-1 MercMonitor (but not on NMEA-2000).

[mikesxpress]

271° after a 28 minute run in 65° water. Longer run and 75+ water temp is going to push it up some more. Conventional oil starts breaking down at 275°.
Were running a synthetic blend so that goes up a bit.
A full-synthetic oil will withstand temperatures in excess of 300 degrees. Deduction says 285° and our oil will break down. That explains why these don't "make oil". It cooks off the moisture.

At what temp does the alarm go off?

[EuropeanAM]

That info is specific to each PCM calibration (honestly don't see a max spec listed in the manual).

Will make a note to check the threshold (at least a range) on the next one I rig.

[mikesxpress]

Mercury should have an optimum run temperature for the oil and what the high oil temp alarm is set at?
The local techs don't know what either of these are. Calling into Mercury resulted in the same, they couldn't provide answers.

[EuropeanAM]

They surely do. However very few actually have access to the Calibration/Engineering Parameters. There are some "general rules of thumb" but I strongly suspect these engines are running some pretty high oil temps compared to some of the early 4-strokes.

I'll be sure to ask and notate info when available.