How bad is it?

[heatseeker]

Motor is a 1995 yamaha c85

Ran the boat last sunday a total of 40 miles at crusing speed.Not one hiccup. Approximately 500 yards from the ramp i opened her up. As i got into the no wake zone and slowed down i noticed the motor smoking and lost power. Took off the cowling and the head cover was discolored (overheat).Smoke appeared to be coming out of the top of the head gasket. The motor died and we proceeded to use our freedive fins to row ourselves in the last 20 yards. Pretty funny.

Today i had time to attempt removal of the head. Broke 3 or 4 bolts in the process and the head cover stayed stuck onto the head. Attatched youll find pictures i took with my phone so sorry about the crappy pictures.

http://s887.photobucket.com/albums/ac72/silentthreatinc/?action=view&current=head.jpg

These pictures were taken AFTER i cleaned out some of the salt deposit in the water passages because it was full of deposit. The cylinder walls are smooth and show no damage but it looks like detonation is the cause. Looks like theres pitting on the cylinder heads.

The carbs were recently tuned, water seperator is new, gas was new, mixed 50:1, impeller is new.

So how bad is it? can i just change the head and head cover and call it a day? new pistons? complete over haul?

Your thoughts please.

thanks again