I am the original owner of a 1998 boat with a 5.7 250HP Mercuiser I/O
(6.5 years old now). The 1998 Mecruiser brochure I got with the boat
says that this motor has ceramic coated exhaust mainfolds and elbows.

The boat has 320 hours on it and has been fresh water flushed
religously after salt water use and stored on a lift out of the water.

There are no signs around the riser/manifold gasket of leakage and the
spark plugs and oil are clean.

Does anyone here know how much time these ceramic coated exhaust parts
should be good for?

Thank you