smart craft question

[CharlieB]

How accurate is the water temp on a smart craft gauge. My 250XS never reads higher than 114. at idle it reads 105 and jumps up to 114 at WOT. Never see it higher. I'm being told to let it warm up to 120 before hitting wot well that ain't happenin. water pressure is fine. 5 idle 15 at wot. Where is it monitored in the loop.

[Kings Marine nz]

Water temp gauge is dead accurate, reads direct off the PCM, the 3ltr original thermostats where 120f and generally the engine will range between 115 - 122f.
There where lots of issues with the thermostats, particularly the rubber seal. Mercury made a superseded thermo which was 130f and fixed the rubber seal problem, also they made new thermo covers for cyl head as well to help stop rubber seal parting ways with thermo. Remember if the engine runs cold at idle it will tend to foul spark plugs.

[HighVelocity]

Dkramer has the same motor as you. I would sent him PM and compare notes, he has smartcraft too.

HV

[CharlieB]

thanks guys I'll check those seals.

[dkramer]

CharlieB,
my 250xs runs 124 typically and that is off the smartcraft. I also have an analog gauge that reads the same. I have seen it higher when I sucked something up in my LU pickup and both gauges were reading the same but other than that it reads the same, the smartcraft usually reads quicker than the analog however. When I fire it up it reads in the high 90's and climbs right up to low 120's.

Dave