I have a 1997 454 Bravo II raw water cooled.Last time out last year at idle it would be fine.When I would run the boat at higher RPMs it would overheat.I thought t-stat.When the boat was out of water for season I started working on it.I replaced t-stat,raw water impeller and housing,circulating pump,manifold, risers ,spacer blocks and hoses.Manifold,riser and blocks where 5 years old.Everything else was original I think.Nothing seemed to look like the cause but was showing signs of wear.Spark plugs did not look to have signs of water.Did not compression check.Put boat back in water and doing the same thing.Anyone have any thoughts?Thanks for viewing.
