Practical Sailorvideo
How To Change Your Sailboat Engine Mounts
3 August 2024 · 7 min · 14K views
What this video covers
Excess vibration traced to a worn rear port-side engine mount on a 27-year-old Perkins M20 diesel prompts a full four-mount replacement.3:00 Two diagnostic signs flag failing mounts before they break: black rubber dust around the mount base and the ability to twist the mount by hand with the engine stopped.2:09 A failed mount can misalign the prop shaft, stress the transmission, and cause structural damage including water infiltration; a broken mount can damage the engine itself.2:27
The replacement procedure covers measuring each mount's current height before removal — critical because mounts compress over years and heights often differ, as the front port mount on this engine sits higher to accommodate the alternator bracket.4:39 Mounts are swapped one at a time with the engine supported by wood blocks and a scissor jack held at light pressure.3:53 After installation, shaft alignment is checked and corrected using a spark plug feeler gauge between the transmission output flange and the prop shaft flange, adjusting in quarter- or half-turn increments equally port and starboard until the gap is uniform around the full rotation.5:29 New mounts from Parts for Engines (UK) were ordered with fresh hardware.3:17 A CNC 36 with a Yanmar 3QM on Lake Erie provides the opening context.Watch Alignment should be rechecked with a feeler gauge on a regular schedule tied to engine hours.4:59
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