Re: yanmar 2GM20F
White smoke is usually a sign of 'burning' glycol coolant. Assume it's FWC? But a massive coolant leak wouldn't cause a runaway condition, I wouldn't think.
Whatever it is, it sounds expensive.....
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"