Merc 350 Normal Temp? Twins in a 292
 

What temp should a 2001 Merc 350 MPI run?

My gauges were reading with some variation, and instability.

So, I replaced both temp senders and thermostats.

Now both are around 185-190 99% of the time. under load, idle, wide open. They vary a bit as well.
But never over 190.

I already plan to replace the raw water impellers this winter, and inspect the risers, however what temp should these run? The OEM thermostat says 160....

thanks

Thats a little high but never over 200 is my rule, mine usually both run 170 when going fast and 150 at idle. the gauges in any boat are not the most accurate but they give an acceptable range and provide norms and abnorms

Thanks. My old boat only had a large green area, and a red area. Although it stayed a lot more dead center than this one does.

It's never passed 190. You'd think w/a thermostat it could maintain a little better though...

Yeah. From one motor to the next I can assume if the sending units are in a different spot tgecreading could be different too...

You should pull off the plastic gooseneck at the inner transom assembly and check that the line coming from the drive is not choking off. Mine were maybe 1/4 - 1/2 the area they should have been when new. I had the same problem.

Fresh water only 2004 w 6.2s
with 160 thermostats i will see 180 on the gauges.

With 140 thermostats i will see 160