[C320-list] New Engine Mounts

[Martin Raphael]

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
>>
>>
>>
>