[C320-list] Motor mount change out

[wdoc1 at aol.com]

No vibration issues, but beginning to see bits of rust/degrading rubber under the Yanmar 3GM30F engine on my 2000 C320, and the original mounts are looking pretty shabby. Planning to replace them this fall/winter. I assume this is better done on the hard than in the water? 
I was hoping to find a you-tube or guide with detailed instructions/photos, a la Jeff Hare's 'Below-deck Autopilot Installation Guide', but no luck so far. 
Questions:1. Any need to lift the engine or decouple the drive shaft?
2. Per email below need two "100" s forward and two "75"s aft? Just looked online and found stainless/urethane mounts which the manufacturer, Oceanic Innovations, claims are a superior product for Yanmar engines...urethane being resistant to diesel, no rust with stainless...anyone have experience/recommendations with these? 
Thank you in advance,
Bill McConnell2000 C320 714, Diversion 

-----Original Message-----
From: Jeff Hare <Catalina at thehares.com>
To: C320-List at Catalina320.com
Sent: Wed, Jun 29, 2022 9:45 am
Subject: Re: [C320-list] Motor mount change out

There's a great article/resource on the C320.org website titled "Get In Line" written by Jack Harden. There is a spreadsheet last updated by Karl that makes it easy to determine the corrections to be made to get the system running smoothly.  I recommend downloading a copy and keeping it with your boat stuff.  Keep trying, the website is really struggling these days, but will eventually give you what you need.

I've used this a couple times on #809 Woodbine II (now Dodger), mostly after changing between traditional stuffing box and the PSS and back. It takes the adjustment experimentation mostly out of the equation.  System went from having a generally harsh feel to smooth as silk across the RPM range. It's also great for realigning the system after engine mounts are changed.

Just keep in mind that there are several components involved in getting this all running right but assumes the prop is balanced, the shaft is straight and the cutlass bearing is not worn out.  

1. The coupling on the shaft may or may not be perfectly perpendicular with the shaft on all axis.
2. The coupling on the end of the transmission may not be perfectly perpendicular with the engine crank
3. The engine could be angled left, right, up or down (according to the engine mounts).

The 3GM engine rocks significantly when running, but it's important to remember that the rocking (by design) is perfectly centered along the Crank shaft driveline, so it is really pivots and balanced around the crankshaft.  So, the rocking is not an issue WHEN the prop shaft and engine crank shaft are perfectly in line.

This article helps you understand these factors and how to make the subtle adjustments without guesswork.

The PDF Article:
https://c320.org/filemgmt/visit.php?lid=46

The optional Spreadsheet to help you capture the measurements and make the corrections:
https://c320.org/filemgmt/visit.php?lid=45


-Jeff Hare
#17 C355 Solstice
Formerly #809 C320 Woodbine II

-----Original Message-----
From: C320-list <c320-list-bounces at lists.catalina320.com> On Behalf Of Greg Flanagan
Sent: Tuesday, June 28, 2022 9:43 PM
To: C320-List at catalina320.com
Subject: Re: [C320-list] Motor mount change out

Hi Ken,

Sorry for the delayed response, we were out sailing (go figure). Leave the engine brackets alone and in place. Remove the two horizontal bolts in each mount. The large third horizontal bolt is part of the mount. Use it to adjust so you can slip the mount in (one at a time) and then adjust snug to take the engine weight. If you can assume the engine/shaft was originally aligned, you will be close. Then you minimally adjust each until aligned. 

Hope this helps,

Greg

> On Jun 25, 2022, at 10:21 PM, Ken <kspir4 at cox.net> wrote:
> 
> Thanks Greg! Not having to lift it will certainly simplify the project. Do you remember if the “mounting bolts” you removed were the horizontal ones that hold the brackets to the engine or only the vertical ones that hold the bracket to the rubber mount itself?
> Thanks again for the response.
> Ken
> MoonDancer 1089
> 2006
> 
> Sent from my iPhone
> 
> > On Jun 23, 2022, at 9:56 AM, Greg Flanagan <greg.flanagan at shaw.ca> wrote:
> > 
> > Hi Ken,
> > 
> > I changed out my mounts 2 years ago. Your boat is only slightly newer than mine so you’ve done well with yours. I did this with a friend who also happens to be a diesel mechanic certified by Yanmar. We did not need to lift the motor. We loosened all the mounting bolts (needed a breaker bar for a couple) and then replaced the mounts one by one. With that kind of help it took less than an hour. He then adjusted each until the engine was perfectly aligned with no “chattering” of the drive shaft throughout the RPM range. This was really just fine tuning the mounts.
> > 
> > Good luck,
> > Hoop Dancer #1076
> > Sidney, BC
> > 
> > Greg
> > 
> >> On Jun 23, 2022, at 6:13 AM, Ken <kspir4 at cox.net> wrote:
> >> 
> >> Ahoy,
> >> Looking for advice on motor mount change outs. During shakedown this year I noticed some vibration in the shaft and heating in the shaft seal. Once in the slip, I put trans in neutral and could easily turn the shaft in both directions by hand from down below (so it’s not the seal). Started the engine (yanmar 3ym30) and shaft vibrated in what appeared to be a bit up/down and left to right. Engine starts easily and sounds good when running (so doesn’t appear to be a cylinder issue). I checked the motor mounts and all seem to be in various states of wear. One or two appear o have upper metal cover in contact with lower metal base. Fairly certain mounts are the root cause.
> >> I’m ordering two 100s for forward and two 75s for aft. Is there any advice on:
> >> (1) how to lift the engine (e.g., where the lifting points are To lift from above or what kind of Jack fits underneath and where to place it to lift from below)
> >> (2) is it necessary to remove the support brackets (The bracket that connect the top of the mount to the engine) for each Mount? Likely have to remove that bracket for the port aft mount due to accessibility (or lack there of).
> >> (3) any other advice for the changeout or the subsequent alignment? I have the basic process down for alignment but welcome any advice not included in the owners manual.
> >> Many thanks,
> >> Ken
> >> MoonDancer 1089
> >> 2006
> >> 
> >> Sent from my iPhone
>