[C320-list] C320-list Digest, Vol 138, Issue 1

[warren updike]

RE: Perkins shaking at low rpm.  For those concerned about shifting at
speed, I don't worry about it. A Perkins authorized mechanic told me that
the gear was designed to stand a full speed shift. While I haven't tried
that, why tempt fate, I do routinely shift into and out of gear while the
engine runs between 1200-1500.  I do this in docking situations, especially
where currents are involved and idle speed is not enough of a kick.

I have learned to keep the rpms at or above 1000 to avoid the "Perkie Shake"
that seems common to this engine. I'm confident that my mounts are tight and
firm. It's possible that a valve or injector is sticking at low speed; but,
another mechanic told me that some small diesels just do this. 

One cure is to adjust the fuel cable to the high pressure pump so that it
won't drop under 1,000 rpm.  I was thinking about that while I was training
myself to avoid the low rpms.  I probably won't do it now.

Check with a Perkins mechanic before spending $$$ on mounts, injectors, etc.
that may not be needed.


Warren & Pattie Updke
Catalina 320, #62, "Warr De Mar"
Middle River, Chesapeake Bay




-----Original Message-----
Likewise, the shaking starts at just under 900, where I like to shift, so I
engage the new gear and bring the revs up to 1000 or higher, No shaking.

Kirk
#124
----- Original Message -----
From: "Pat Moriarty" <patm at psiurethanes.com>
To: <C320-List at Catalina320.com>
Sent: Thursday, June 26, 2008 5:24 AM
Subject: Re: [C320-list] New Engine Mounts


> Only one thought, are you sure about the shaft and prop being true and 
> balanced?
> Mine only shakes at dead idle when starting from sitting still or changing

> directions but at 1000 RPM no shake, 1994 Perkins 600 hrs original mounts.
>
> Pat #130At 07:55 PM 6/25/2008, you wrote:
>>I just replaced my non-stock engine mounts with the stock Perkins mounts 
>>per the thread below.  To my great distress, the engine now vibrates 
>>wildly, to the point that the shaft bounces against the shaft tunnel when 
>>in gear.  I had hoped that the softer stock mounts would solve a 
>>long-lasting vibration and noise issue I have been experiencing.  Now my 
>>mechanic says the real culprit may be in the valves and they will be 
>>checking that out tomorrow. He says he has encountered 2 other Perkins 
>>that have serious valve rocker wear, and that this can cause the 
>>vibration.  Have any of you heard of this problem or experienced it 
>>yourselves?  Right now I'm feeling rather foolish for having invested a 
>>huge amount of money in new mounts when those may not have been the 
>>culprit.  BTW, mine is a 94 Perkins M30.  So let this be a caution before 
>>blindly switching out motor mounts.  I may have to just go back to the old

>>mounts and live with the annoying but tolerable vibration.
>>Martin Raphael
>>Rhapsody #108
>>----- Original Message ----- From: "Martin Raphael" <mraphael at q.com>
>>To: <C320-List at Catalina320.com>
>>Sent: Sunday, June 01, 2008 7:16 PM
>>Subject: Re: [C320-list] New Engine Mounts
>>
>>
>>>Just a thought here...the engine will vibrate the same way in relation to

>>>RPM whether you have old or new engine mounts, wouldn't it?  Engine 
>>>mounts will affect how that vibration is transmitted to the hull, and 
>>>thus what we hear or feel.  Stiffer mounts will transmit more directly to

>>>the hull...softer mounts will absorb vibration.  So I wonder if Mike's 
>>>new mounts were actually "softer" than the worn mounts he replaced.  I 
>>>say this because some years ago (2003) I had new engine mounts installed,

>>>and the engine noise and vibration, especially at low RPMs, went up 
>>>tremendously.  I have always thought this was because the new engine 
>>>mounts were much stiffer than the originals.  Other thoughts?
>>>Martin Raphael
>>>Rhapsody #108
>>>----- Original Message ----- From: "Kirk McCullough" 
>>><kirk.mccullough at telus.net>
>>>To: <C320-List at Catalina320.com>
>>>Sent: Wednesday, May 28, 2008 9:18 AM
>>>Subject: Re: [C320-list] New Engine Mounts
>>>
>>>
>>>>Mike
>>>>
>>>>Good advice, I'll add new mounts to the list. I have always put up with 
>>>>the "Perkins shudder" at low RPM, made even a little worse with the high

>>>>pitched Kiwi prop when in reverse.
>>>>
>>>>Kirk
>>>>#124
>>>>----- Original Message ----- From: "Mike Shoffner" 
>>>><drshoffner at yahoo.com>
>>>>To: <c320-list at lists.catalina320.com>
>>>>Sent: Sunday, May 25, 2008 6:08 PM
>>>>Subject: [C320-list] New Engine Mounts
>>>>
>>>>
>>>>Over the years there have been threads devoted to the vibrations at low 
>>>>RPM's of the older boats with Perkins engines. I've noted this with my 
>>>>boat ever since I boughtit 4 years ago, and I've just attributed it to 
>>>>being a characteristic of the Perkins engine. Recently, because of my 
>>>>cutless bearing wearing out in one season of use, I had my shaft 
>>>>allignment checked and was advised I needed new engine mounts. What a 
>>>>difference!! The old "Perkins vibrations" apparently were due to worn 
>>>>engine mounts' and with new mounts there are zero vibrations at low 
>>>>RPM's. At higher RPM's engine noise and vibrations are also noticably 
>>>>reduced as well. Mine is a '94 model and probably needed new mounts for 
>>>>several years. I would advise owhners of more mature boats to consider 
>>>>having their engine mounts replaced if they're having problems similar 
>>>>to mine.
>>>>Regards,
>>>>Mike
>>>>#171
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>--
>>>>No virus found in this incoming message.
>>>>Checked by AVG.
>>>>Version: 7.5.524 / Virus Database: 269.24.1/1469 - Release Date: 
>>>>5/27/2008 1:25 PM
>>>>
>>>>
>>
>
> Pat Moriarty
> PSI Urethanes Inc
> PH: 800-888-5156  Fax: 512-837-8733
> Please visit our web site at
> www.psiurethanes.com
>
>