Engine seemed to run fine. shut them down for a spell on the lake yesterday. went to restart and starboard engine would not start. at first I thought battery or starter, but then hear a clunk. I opened the hatch and tried it and see the pulleys nudge and then no turn but rather an abrupt stop. 329 hour's. I am expecting that something may have come apart in the valve train and dropped a valve. What say you? What are these engines more likely notorious for? I guess it could still be a starter if it grenade. Weird that it just seemed to run fine, idled and then shut it off. No noise. I had her turned back even as my 12 year old daughter was steering/driving the boat prior to shutting it off.

Check tha t you have not got water into the motor , friend of min had same thing happen dif motor but he swiched motor off waiting for me to launch and when he went to start CLUNK .it was a riser gasget on a new 454 back in 1992, i know your 496ho does not pass water through the gasget but could be bad manifould .

Pull plugs and see if you can turn motor over by hand with breaker bar on balancer nut.

Do This !

I took it to the local Chevy dealer that's a friend of mine. he determined that it was definitely the starter. Thank God. Now I just need to locate a marina that will change it. He said that he was not comfortable with changing it and sees no way but to pull the engine.

any body in Michigan that's good that is not too busy?

No water in oil. so don't believe that was an issue.