Temp 2.5 EFI running cold

[ToffenG]

Hi!
If I am correct the Merc 2.5 EFI engines tends to run cold at cruise speed (4.000 - 5.000 rpms). I have bought two, and prepare next summer great event. I Norway the sea temp varies a lot. It span from 43F in the spring to 65F in the summer (sometimes 77F, unfortunately seldomÂ…).
I presume correct temp for the engines is 120F - 160F to avoid cold seizing.
Those engines have restricture discs, not termostats. Would termostats solve this problem.
Cheeeers, Toffen G

[STV_Keith]

With water temp at 55F, I have seen my 2.5 run as cold as 100F. When the water temp comes up to 75F, I have seen it run 140F.