1996 yamaha 90 2 stroke no water flow

1996 TRLU 90hp 2 stroke overheated the other day while out. No water from the telltale.
Disassembled and replaced the housing impeller and gaskets. Pushed water through the telltale down ward and it came out the bottom of the lower unit both with the lower on and off, so I do not think there is a clog in there.
Started it up, still don't get any flow out the telltale.
Could this be a thermostat issue? I have rinsed it every day after use with fresh water and noticed little buildup when I took it apart.

Any ideas would be appreciated.

I don't think it's a thermostat issue. If the water pump is doing its job and you have no blockages in the lines, you'll get water out of the exit hole (regardless of whether the thermostat is open or closed).

What water pump kit did you buy? If you can back-flush it through the exit hole, I would say your problem is the water pump, or a clog near the water intake. It's possible that the clog will only occur when water is being pumped up, and not when you back-flush it.

I'm wondering why the pump kit you replaced failed. I mean they do wear and either the rubber impeller or gasket will erode, or both....but you would see this when disassembling. Hard to miss black shredded rubber debris.

As as the previous member stated, even if you've got blockage in the cooling system you'll still get water out the t/t as its the path of least resistance. Only a few things that could be the issue w/no water after replacing kit....impeller not engaged w/woodruff key, housing tube gasket is missing, or mid section water tube not linked w/housing. Troubleshoot from l/u up....water intake, drive shaft turn key, key turns impeller, impeller propels water thru housing, thru water tube, thru t/t.