Merc 350 mag mpi HELP! 200°

[Timbolex]

OK follow up on today's post, ran the boat fir 4 hours today, temp guage still a little wacky, creeping up to almost 210, thermostat housing always stayed at 160ish, exhaust manifolds ran 190/200ish and risers were a cool 100° all day! I'm pretty certain it's a gauge issue, thanks for all the input, it really helped!

 

[dubs283]

I'm pretty certain it's a gauge issue

Might be the guage but don't rule out wiring or possible temp sender issue

 

[QBhoy]

Hi. Assuming the engine isn’t original to the boat, looking at the lovely classic dash and gauges. Can I ask if when the new engine was fitted…was the alarm warning system fitted too ? Do you get a beep when the key is turned ?
Likely a gauge issue, but thought I’d ask anyway.