"Thermostats are in all engine
"Thermostats are in all engines, auto and marine to make sure the engine runs AT the temp that the designers want it to. Removing a T'stat under any condition is not a good solution.
RE: the cold hoses to the manifolds. If the manifolds are more that couple of seasons old, or the impeller you removed had any pieces missing, you may have an obstruction that is preventing water flow to the manifolds."
1969 23ft ChrisCraft Lancer
Merc 5.7L 260HP/ Volvo 280
1972 22ft Bristol
Honda 7.5HP 4 stroke Long shaft