This morning I encountered a problem with my yanmar. After filling with oil, coolant, cleaning raw water filter and a test run last night she broke down on me just before I was to leave this morning. Symptoms:
Massive quantities of white smoke (smells like steam?)
Black soot-like slick mixed with raw water coming from exhaust (unburned fuel?)
Unprovoked revving to high RPM and (here's the odd part) the complete inability to shut down. When choke is pulled the engine just keeps running away until it apparently can't take it anymore. I fear doing more damage if I attempt to run the engine again. Mechanic coming at 8 AM tomorrow morning and mentioned worst casescenario being a rebuild. Wanted to get the thoughts of the sailing community first.