Normal Operating Temperature for a 3.0 mercrusier??

[MuskyHuntr]

I was wondering what the normal operating temperature should be on a 3.0 Liter mercrusier 140hp stern drive?

I have a little less than 145 degrees running at 1000 RPM.. Matter of fact I trolled all day on Saturday (like 12 hrs) at 1000-1100 rpm and the temp gauge never moved from that.. Picked up and ran in running 3000 rpms for approx 15 to 20 minutes and the temp gauge rose to 175 degrees...
Is this normal or is there something wrong? Should it be approx. 145 degree's all the time.. ????

any input would be greatly appreciated..

Thanks
Mark

[Macrenovations]

Hey Musky I had the same motor she ran around the 150's at or below the 1500rpm range and would only jump to 180 when she was above 1500. I would say your motors running at the norm. Anything under 125 or above 200 temp I would be concerned about. Trying running for 30min or so next time out see if the temp jumps and most important how fast it takes the motor to cool down ones at or below 1500rpm.

[spareparts]

143 is the stock thermostat on older 3.0L's newer ones run up to 160