mercury 150xr6

[nikos]

good evening
i have amercury 150 xr6 2003y/o with 150hours
And in my last boat ride after 10 miles stop the engine and all is good after 2 hours try to start the engine and the engine don t start,I opened the left head and the 6 pistons is Has been destroyed.
Do you know why this happened? I did not have any temperature at all.
thank you

[nikos]

383050383051

some foto of block and head

[John800]

Looks like one cylinder ran lean

[FORBESAUTO]

Detonation due to lean or timing high on that cylinder. Need to go through fuel system thouroughly and index flywheel for that cylinder and check wot timing on #6. When I had a new set of switchboxes that had a bias problem, #6 was the cylinder it would fry, found it had 5 degrees more timing than #1.

[nikos]

thank you for reply.