I've owned my 1997 2700SCR with a single Mercruiser 5.7 liter engine and Alpha One outdrive for a little over a year. The performance is driving me INSANE but my boat mechanic says it is as expected. My MAX speed is 16.5 knots at 4,000 RPM (there is very little extra weight on the boat beyond two regular size people, minimal fresh water and minimal fuel). That speed isn't even on a good plane.
Anything above 4,000 RPM and the engine temperature spikes way above 225 degrees which scares the bejebuz out of me. It is fresh water cooled.
What speed should I be seeing at 4,000 RPM on this small single engine? The engine -and- outdrive were just serviced a month ago.
My mechanic also said that the impeller is fine and the temperature is normal when the engine is pushed that hard, although from what I read the normal operating RPM for this engine is 4400 - 4800. He also said it has the correct prop spec'd for the boat.
Suggestions? Would love to hear what speed and temp this should be at. Also can I increase the size of the heat exchanger, put a lower temp thermostat or something else because it's running so hot?
Does anyone know a good boat mechanic in Seattle that I can call and make sure my other mechanic isn't missing anything obvious?