Mercruiser 3.0L zero compression

That's right Slavi, he did!

Called us last week saying that he never received any of my 8 mails (3 addresses), so he wasn't aware of my curiosity.
He said they (?) had replaced the head gasket prior to his holiday last year; because the gasket came without bolts these were bought locally. Not the specified ones, just bolts with the right length and thread, so most of them snapped within a few hours. The escaping gases burned not just the gasket but also the bridges between the cylinders.
He had it repaired for a little over $2000 but skipped this years holiday so he didn't know anything about the repair quality.

 

Somehow a rag or a loose piece of sound deadening carpet stuck in the carburetor throat? Old paper air filter got wet (that makes them just dead tight)?

Will result in no air into cylinders, ie no air to compress (or burn for that matter).