[C320-list] Severe vibration at 1000 RPMs after engine mount replacement

[Paul Borghese]

Do you have the idle set to 1100?

On Fri, Dec 11, 2020 at 11:34 AM Age Of Aquariums <dan at ageofaquariums.biz>
wrote:

> my perkins does the same thing , i don’t go below 1100
>
> > On Dec 11, 2020, at 8:17 AM, Paul Borghese <packetpaul at gmail.com> wrote:
> >
> > A boatyard replaced the engine mounts in my Cat 320 Perkins M30 engine.
> The
> > engine is noticeably smoother at all RPMs except one, 1000 RPMs.  At
> > exactly 1000 RPMs the harmonic vibration causes the engine to shake
> > violently.
> >
> > The vibration occurs every time on every transmission setting ( neutral,
> > forward, reverse).
> >
> > Any ideas as to the issue?  I have an uneducated theory. The yard used
> > off-brand engine mounts that were not tuned to the engine causing the
> > severe vibration.  Or maybe the bolts are not torqued to the correct
> > specification.
> >
> > Thoughts?
> >
> >
> > Paul
>
>