serious problem with 2005 Optimax 225?

everyone,

i am looking for some information. I was in a tournament this last Saturday, When it came time to launch, i got about 1 mile from the ramp when my engine sudenly died, no alarms. I tried to restart it, and nothing. I checked all the usual stuff turn off/on the main power supply and go back to the console and start the engine, everything seems fine, running smooth. I start off again and get about 200 yards and the engine goes into guardian mode then dies. I start it right back up and it has a rattle to it. So i immediately shut it down. I felt all of the cylinders and none seemed hot. I was getting a good tale tale. I also didn't see anything that was out of the ordinary. I pulled all of the spark plugs today and all looked good until i got to the last one. It was a dry and looked like it got hot, like a piece of metal was melted to it hard to discribe. i also noticed that the plug wire was rusted at the spark plug end. I looked in the cylinder as best i could w/o pulling the head, i did not see anything alarming. The engine ran at best with the rattle for 1 minute.

i have attached a photo of the sparkplug. Where do i start????What do i do???? i am mechanically inclined.

thanks for the info.

Re: serious problem with 2005 Optimax 225?

Pull the head and see how much of the piston is left and how bad cylinder wall are scuffed. Get yourself a manual(below) take a bunch of pictures...Not a very Merry Christmas.
http://1manual.com/Mercury manuals/Service Manual PDFs/OptiMax/859769r1/cover.pdf

Re: serious problem with 2005 Optimax 225?

will do that. what could of caused this to happen?

Re: serious problem with 2005 Optimax 225?

Overheat, lean fuel mixture, lack of lubrication, ignition timing or any combination of the four.

Re: serious problem with 2005 Optimax 225?

thanks for the information. I will pull the Head and post pictures. I think i can rule out the Overheat. I felt the engine. Never was hot on any of the cylinders. I will see what the piston looks like

Re: serious problem with 2005 Optimax 225?

Update!!!!!

had the engine rebuilt. I had a ring cease up. I had lost compression in the one cylinder. The slapping noise i heard was the piston. Walls were not damaged. Have had the boat on the water for about 3.5 hours. seems to be running good. I blame myself for the failure. Was not using Quick Leen in the gas.

Also my mercury fuel line was completely deteriorated. Grey line.