1991 ski nautique overheating

[KSbarney]

Have a 1991 ski nautique and have concerns with overheating. Typically temp gauge reads around 160-165 but will climb gradually to 170-180 with tubing or skiing. However starting at the end of last season and this summer the temps seem to be a bit higher and the temp gauge will often be max >200 when I turn the boat off and then back on. Temp will go back to 160-170 fairly quickly when I start moving. Is this normal? what temp should the boat run?

Had a new impellar Put in 2 years ago and had it looked at the end of last season and it looked good. Had a new 142 t-stat put in this year.

also wondering if maybe my temp gauge or sending unit are not working?

any suggestions?

[Stevemo14]

I'm pretty sure you should be doing a new impeller every year.

[bozo]

Yes, you will get an increase in temp when restarting after running. Your overall running temp is higher than it should be. Could be a loose belt on water pump, some sort of clog in the water system, maybe the impeller disintegrated and is partially blocking the thermostat opening or even the new thermosat is bad. For advice on these things contact skidim.com (you can send an email describing your situation. Skidim has been around for along time and speciallize in inboard ski boats

[SilentSeven]

Frequently, running hot is associated with air leaks on the raw water side of the intake water system. Checking all your hose clamps and fittings is a good starting point...

[KSbarney]

I really appreciate all this advice. Sending an email to skidim today.
looked at the hoses - not sure I’m looking at the right ones.
what about a new sending unit for temp gauge?
have been sidetracked with another issue so thanks again