'89 Sport Running Hot

[Link]

I have been reading all the posts I can find on overheating and need some help figuring this one out. After being Nautique-less for several years, I bought an '89 Sport Nautique with just over 1,000 hours on it. It idles at 160, but creeps up to around 170-180 at cruising speed (2,700-3,000rpms). If I run it any harder than that, it continues to heat up to 185-190. When I pull it back down to an idle, it settles in around 170.

I put a new impeller in, tightened all the hose clamps with a 5/16 nut driver, checked the trans oil cooler for blockage (there was none) and checked the strainer (no blockage). The thermostat (143) was changed a few years back. I pulled the pump apart to pull the thermostat, but it was seated under the gasket. I didn't have another gasket, so I decided to wait to pull it out.

Couple of questions:
1. How hot is too hot? I have seen several mentions of 170 being normal. Do some models just run hotter than others? I seem to remember my old Nautique ('88 2001) ran a bit hotter than normal. Is 170-180 dangerous?
2. I see references to O-rings for the strainer, but can't find a picture. I didn't see one when I unscrewed the bowl, but it has suction. Am I missing it?

[Nautiquehunter]

Are you sure the gauge is accurate?

[Link]

I am not sure if the gauge is accurate. I put my infrared thermo gun to the block, head, pump and got different readings, but they were all less than the gauge read. This led me to believe the gauge was bad, but I don't know exactly where I should get a reading to know for sure.

I was out today and it ran around 160 all day only creeping up to 170 briefly after coming back down to idle. It quicly returned to 160 though.

The last thing I did yesterday was flush the screen in the RWP and put the bowl back on. Since it ran cooler today, it leads me to believe that air is getting in. Maybe it sealed correctly when I put it on yesterday?

Still can't figure it out.

[Link]

Still Running Hotter than Normal

Update:

I tightened all the hose clamps with a 1/4 inch ratchet, replaced the impeller and put an O-ring in the strainer. The temperature started out around 150 for the first few runs. After awhile it heated up to 160 and stayed there for awhile. After starting and stopping (pullying the kids on the tube), it heated up to between 165-170. All this was at 2,500-2,800 RPMs. I opened it up to 3,200 and ran for 10 minutes or so and it crept up to 180.

I opened the cover and shot the sensor with my IR gun (sensor just behind the water pump-I believe that is it). With the gauge reading 180, the gun read 155. Bad gauge? Bad sensor? Wrong place to read the temp?

It just seems strange that the temp would creep up the longer I run it even if it is just a bad gauge.

I could really use some help. Thanks!

[Nautiquehunter]

The best place to get a temp reading is at the thermostat housing it should be close to real temp. Try a new sender
they are cheap and may fix the problem.