inboards

Question
One of my inboards, a 350 mercruiser, seems stuck.  Just six weeks ago it would turn fine. I think it is nothing mechanical, just some light rust.
I was thinking pouring some diesel fuel/kerosene etc in the carburator.
Thanks in advance

Answer
Hi Doug...Thank you for selecting the undersigned to reply to your question.

Why has the engine seized? Was it due to a lack proper maintenance, storage preparation, deteriorated/fractured water jacket(s), head gasket failure, or freezing?

First, have a qualified mechanic trouble-shoot the source and cause of the seizure.

Secondly, get the engine magna-fluxed. It will determine the presence or absence of any fractures within the block, and whether it is economical to repair.

Safe Boating
Ron