My 2005 27 has slowed down
 

When my boat was new it would run about 68mph. It now runs about 62mph. Full tank 1 person on board. 496HO with about 200 hours on it. Only seeing about 4800rpm. Ideas?

:food-smiley-007:

This should get you started............https://www.offshoreonly.com/forums/...e-problem.html.

Scan the engine and service the fuel/fuel injection system (have injectors flowed). That is where I would start. Also what is the condition of your prop? Has it been measured and blades verified true?

take a look at the prop to start. Second what about routine maint times such as a new fuel filter? Have you looked and changed the plugs/wires and the cap and rotor? If you haven't that's my guess as the culprit.