[C320-list] Vibrations at certain RPM Range

[John Meyers]

LESSONS LEARNED.

As a follow up to my earlier post .... I finally discovered and had
corrected the problem with clatter type noise on the boat in a certain
range of RPMs in both in-gear and neutral which made me think that it was
not an alignment problem.

Thanks to all who contributed to possible causes and solutions. There were
suggestions that the motor mounts were the problem. I had stated that my
motor mounts still had lots of room between the motor and hull sides of the
mounts.

Since then I had noticed that on the starboard aft mount the lock washer
was "sprung" so I tightened up the nut and still had the noise. I had a
couple of mechanics listen to the noise and they both said I had a valve
lifter problem. So, yesterday as I was prepping the boat for the "valve
job" by removing the wood part of the bulkhead above the engine (an easy
thing to do, BTW) I noticed that the engine part of the mount that I had
tightened was much lower than the others.  I had already arranged for the
mechanic to also do an alignment and told him what I discovered and
suspected that when the upper nut on the mount was loose that the lower nut
worked itself down before I tightened the upper nut.  When he removed the
four bolts connecting the engine shaft to the propeller shaft the engine
DROPPED a significant amount (maybe a quarter inch). He then corrected that
level of that engine side mount. He then found that the alignment was
correct after that.  I started the engine and NO NOISE like before at all
RPMs that I use. YIPPEE!!!. He then did the valve lifter adjustment (one of
the six was too tight, one was okay, and the other four were in need of
adjustment which also made the engine quieter. BTW, the whole valve job
took him much less that an hour.

Lessons Learned.....
Every time I check the oil I WILL check the nuts on top of the engine
mounts.
If the any of the nuts are loose I WILL have the shaft aligned ASAP.

Thanks to all who responded and thanks AGAIN for this forum.

John Meyers
Wind Chime #406
Muskegon, MI

On Mon, Aug 12, 2019 at 9:03 AM <sail-ability at sympatico.ca> wrote:

> I have one. What are U willing to pay+shipping.
> JohnM
> 1999#574
>
> Sent from my iPhone
>
> > On Aug 12, 2019, at 8:34 AM, kskis at aol.com wrote:
> >
> > As I responded recently, my "whining" or "singing" between 1800 and 2500
> rpms in forward gear only, could be a prop issue.  I have read that some
> prop people are familiar with creating an "anti singing edge-a chamfering
> of the trailing edge, typically on the suction side..." (ref:HydroComp,
> Inc.).   If a prop issue, this could be determined by replacing the prop
> with a "working" 3-blade prop from another C320.  Wondering if anyone can
> direct me to a fixed 3-blade 9x15RH prop for sale?  Or any other
> suggestion?  Thanks.  Neil Kornblatt Harmony #973
> >
> >
> > -----Original Message-----
> > From: John Meyers <jcmeyers7 at gmail.com>
> > To: C320-List <C320-List at catalina320.com>
> > Sent: Tue, Aug 6, 2019 10:38 am
> > Subject: [C320-list] Vibrations at certain RPM Range
> >
> > Starting about 3 weeks ago the boat is making a loud racket when the
> engine
> > is revving between 1500 and 2000 rpm. mostly in the rear of the boat but
> I
> > cannot pinpoint the source. This occurs both in gear and in neutral so
> not
> > suspecting shaft alignment. I suspect that it is some harmonic thing. All
> > motor mounts look good and solid and well attached with over a quarter
> inch
> > between the metal parts. I have check both feeling and/or removed just
> > about every thing in the lockers like spare prop, spare anchor, propane
> > tank, and other items that might be shaking while the noise is
> occurring. I
> > have felt the fuel tank and engine and nothing feels different than when
> > the noise is not noticeable. I have even gone below the boat and felt the
> > shaft prop cutlass, rudder and all seem solid. The shaft and cutlass
> > bearing were replaced a couple years ago. I have checked the steering
> > mechanism.
> >
> > To explain the noise/clatter it sounds like a loose hatch, door, or
> > equipment is shaking.
> >
> > At low revs and higher revs the noise is not there.
> >
> > Has anyone ever had this problem or know someone that has/had this
> problem?
> >
> > Thanks for all your help in past, present, and future. I rely on the
> > questions and answers this list provides.
> >
> > John Meyers
> > Wind Chime 1997 #406
> > Muskegon, MI
>