Took my boat in to be looked at as I was out last Saturday when it when into guardian mode. Boat wouldn't go over 3000RPM. They couldn't pull any error code off of the computer so they hooked it to a prop dyno and they believe it to be a valve spring or broken lifter. They are tearing it apart to determine for sure what the issue is but they are confident that this is the issue.

The motor is only an 2005 with ~ 150 hours on it. Bad news is it is out of warranty. Very low hours for a 2005 and the boat hasn't been run hard. I asked the guy at the shop what the issue could have been b/c all I hear is how these 496HO are pretty well bulletproof. Obviously not! He said he doesn't know for sure yet but he suspects that there was probably an inclusion in the spring that finally broke.

What type of cost am I looking at here?

I've been hearing $800 to have them done on my HP500 up in the Detroit area.

I would be more concerned if the "shrapnel" got in somewhere and did more damage, but hopefully not. Good luck.