After much contemplation, the “old” Lombardini LDW 502 M (acquired in March 2007, but with only 13 hours’ running time, all since March 2022!) is to be retired, rebuilt, looking for a new home. (See earlier posts “Grrrr” and “Good news, and less”.)
Ultimate cause of engine failure was inadvertent absence of anti-siphoning valve on raw water intake.
In its place, a new Lombardini LDW 702 M, bringing 18 hp and a cast iron block (compared to the 502’s 11 hp and aluminium block). Conveniently, the 702’s bottom end is precisely the same dimension as the 502, right down to location of the brackets for fitting to engine mounts and fitting to propshaft.
It’s just a bit fatter and taller. So it should drop straight in.
Inevitably, that is not what happened: the original engine mounts didn’t fit because one seems to have been relocated with adjustment of the old engine’s bracket to avoid internal structure; on adjusting the new engine’s bracket similarly, it was discovered one of the old engine mounts perished in a fuel leak (and they come in packs of four); deciding to replace all engine mounts, their epoxied bolts couldn’t be removed, so new mounts have had to be rotated by 15°; new mounts plus rotation exceeded necessary tolerances for commissioning certificate. Doubtless resolution will be found.