"Keith Hughes" wrote:

Very dependable engine though, not quiet at all, and lots of
vibration, but was hand-crankable (BTDT). WOT was IIRC 2800 RPM.

One lungers are a beast when it comes to sound and vibration.

You have the same problem with a Yanmar YSM12.

Only solution I found was to add an AquaDrive which puts the engine on
soft mounts where the resonant frequency is well below the operating
frequency.

I dropped almost 30dB sound level and quit backing screws out of
bulkheads, snapping engine mount studs, etc.

Lew