Thermostat replacement

[Donkado]

Hello all looking for some help. Just bought a 05 Moomba Mobius Lsv, after using the boat a few times it would overheat when not in gear. Running full out temp is fine but as soon as I put in neutral it overheated. I replaced the impeller, cleaned the water filters and now replaced the thermostat with with one I found on a Forum the Sierra 18-3649. When I used it yesterday it didn’t overheat but temp was steady at 180. The thermostat is supposed to be 160. Can anyone advise?

[james yarosz]

Gauge is probally off.My boat does the same thing.

[Donkado]

Gauge is probally off.My boat does the same thing.

Before I replaced the thermostat the old one when running wide open would hold at 160. Is there a way to test the gauge?

[Holdmybeer]

Before I replaced the thermostat the old one when running wide open would hold at 160. Is there a way to test the gauge?

What is the gauge reading completely cold with the key turned on, but not running? Does the 05 have closed loop cooling or sucking lake water (impeller, so I assume closed loop)

Analog gauges with bad grounds and/or lose connections will never read accurately. I would check the back of the dash for any lose connections. Next think about your water pump (not impeller) on the engine. If it is starting to fail it could not be pumping enough to cycle the antifreeze through. Most have weep holes that drip coolant when they are about done working (on cars anyway).

[Team Smith Outback V]

I have had some of the same issues. Have you replaced the temp gauge sensor? It just screws in to the block and is relatively inexpensive on skidim.com. That might be the issue.

[DOCDRS]

Perhaps it is a 180 tstat instead of a 160 in the box by mistake?