If sea water pump is working normally, no matter the condition of the recirc pump, lots of water will cone out if exhaust. A bad recirc pump will cause overheat, usually, but not always limited too, off idle.

I’m not telling you this is your ussue. Just giving you some info on how open cooling works.

Yes boat is new to me, have not had it in the water yet, I was going over it and checking things out prepping for the first outing. Overheats just idling in my driveway. Boat has been in dry storage for a few years. Guy I bought it from had a shop go over it. It seemed to be fine the first couple times I ran it in my driveway but about the third time I let it warm up, it got too hot.

Raw water pump

Changed it. Getting good flow exiting the exhaust.

I thought I had good water flow, it looked like the other motor but it was a blockage.
Bravoitis.

Speaking if which (looks like good flow) And we have all heard many over the years here heat up on the hose but not in the water.

If you are running faster than idle speed many home water systems don’t have enough volume to keep up. ( as sb said)

I have the lower half of the out drive submerged in a 19” deep storage bin, about 40-50 gallons.

That engine uses a 140* Tstat. You also need to use Merc gasket for the thermostat housing to get accurate readings. It has special crush rivets and do not use RTV on it.
What temps are you seeing on the gauge? The alarm should go off it gets to 190ish. The alarm system and sender is separate from the gauge.

I have a 140* stat in now, I did use rtv, but I will re do it without tomorrow. Why no rtv? I am seeing 200 and rising. Also will investigate my alarm because it’s not going off at all.