Thanks all, appreciate the help. I get the “buyer beware” comment but when is the last time you checked torque on all engine bolts standing in a sellers driveway to see if any were broken and held in with silicone. Leaving the bolt head out or disclosing it are the honest approaches.
there is no need to check bolts for tightness in the driveway , what i am saying is a through inspection before purchase will for the most part show a bad patch up job like you have witnessed on your motor..
basically what the PO has done would be what i am suggesting you should do , IE on the really trashed holes poke some devcon in them and push the bolts in to create a seal so as exhaust water cant leak out ,
PO used silicone which probably was in retrospect a bit dodgy but who knows how long ago it was done or how long it would have held up if you had not interfered with the screws.
i must be dishonest because i don't disclose every fix i have ever done on something to a buyer before i sell it to them, nor should i need to.
the joys of buying used outboards.