I have an inboard 454 volvo. Sea water cooled. This year we though the boat was running too hot. It showed my coolant was getting as high as 220-230 F. Removed and cleaned the heat exchange, and inspected and changed the impeller. Impeller was intact and felt soft and flexible. Heat exchange was a little clogged with bits of the anode and what looked like small flakes of rock from the Whittier harbor. Still showed hot on the gauge, used a handheld IR thermometer and zapped the heat exchange and manifold risers.
Gauge looks to be bad. Heat exchange showed a max temp of 180 F. The exhaust risers were much hotter, 211 F!!
I have no idea how hot the risers should be. The engine performs well with no loss of power. Can anyone tell me operating temps for the exhaust and manifolds? Thanks in advance.