[C320-list] New Engine Mounts

[Kirk McCullough]

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
>
>