Engine mounts

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Talisman
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Engine mounts

I noticed several hairline gel coat cracks around my galley sole near the engine area.  All I can think of is they are due to engine vibration.  Could I need engine mounts.  It doesn't feel like the engine is vibrating more than normal but I don't have another boat to compare to.

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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GaryB
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Posts: 570

Enrique,
As to when one would need to change motor mounts I'm not sure. I believe what you are seeing is stress cracks in the gelcoat which I believe is common with a boat that is aging. As long as your engine is in good alignment prop shaft and all and the bolts securing the engine and engine mounts are tight I don't believe you have anything to worry about. I have some and they are forward of the galley along the bilge and some along the bilge near the mast. They were there when I purchased the boat 14 years ago and have not been a problem or changed in any way.

Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine

Talisman
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Posts: 243

Thanks Gary.  Mine are right around the engine compartment on the floor surrounding where the engine is attached.

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

cpntodd
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Posts: 10

Following up on that thread. My 2002 Catalina 36 has always had excessive vibration in neutral at low RPM's. Has anyone else had this issue and if so what was the issue?
Thanks,
Todd
s/v: Prism

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newguy
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My 2004 also has excessive vibration at low RPM (neutral or in gear), getting much better after about 1200 RPM.  I've always assumed the rubber in the engine mounts, especially the rear mounts, no longer had sufficient elasticity.  I have yet to replace them though, but I've read other places that good results have been achieved when they have been replaced.  No idea on how long they should last, but they are often exposed to oil, water, temperature change, and vibration.  I'd say anytime your raw water hoses need replacement that it might be time for engine mounts.

Going with an after-market mount for a M35B engine is much more difficult than other engine models.  I think the path of least resistance would be to replace the mounts with OEM mounts, perhaps just doing the rears first.

Nick Caballero
Retired C36/375IA Mk II Technical Editor

Talisman
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Posts: 243

It looks like a big job to me fronts or rears.  Wouldn't you have to disconnect the prop shaft or the transition?  I am also concerned with realigning afterwards.

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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Chachere
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Posts: 825

[quote=Talisman]It looks like a big job to me fronts or rears.  Wouldn't you have to disconnect the prop shaft or the transition?[/quote]
   Not as bad as it might seem, Enrique.   This was one of the first jobs I had to do on our Mk1 when we bought her 6 years ago.  As I recall, the process was something like this:
-  remove the bulkhead (between the galley and the aft cabin) as well as the box that covers the exhaust riser in the aft cabin.
-  disconnect the prop shaft, and disconnect either the exhaust riser from the engine or disconnect the hose from the riser to the waterlift muffler.  All the other connections (hoses, control cables, electrical connections) should have enough slack in them that they don't need to be disconnected.
-- remove the upper bolts on the mounts
-- rig up a hoist (I used a come-along) to a 4x4 that you lay across the companionway opening and down to the engine (which has a lifting hook)
-- raise up the front of the engine a few inches so that you can unbolt the mounts and remove (and replace) them. 
-- raise up the back of the engine a few inches so that you can unbolt the mounts and remove (and replace) them.
-- reverse the above process

[quote=Talisman]I am also concerned with realigning afterwards.[/quote]

  You'll have to do that, but if you know your engine is at the right place in terms of height alignment at present, you can get a head start by taking careful measurements of the current settings of the old mounts before you start.  That way, once the engine is lowered onto the new mounts, you can set them at the same heights as before.    You'll still have to check the lateral alignment (although I think penciling in the positions of the old mounts may help on this as well.

    But if you haven't aligned your engine in a while, you should be doing this anyway -- the damage a mis-aligned engine can cause (and the work required to repair that damage) is very much something you should want to avoid! (see https://www.catalina36.org/forum/technical-discussion/shaft-tube-removal to get an idea of the consequences)

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

Talisman
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Posts: 243

Wow. Thanks.

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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newguy
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Hey Matthew.  Assuming you replaced your mounts because of excessive vibration.  If so, did replacing them meet your expectations

Nick Caballero
Retired C36/375IA Mk II Technical Editor

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Chachere
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-

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

Talisman
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Posts: 243

How do you align the engine or even know if it is misaligned?
 

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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Haro
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Posts: 403

To find out if the engine is miss aligned - loosen the four screws holding the propeller shaft coupling to the transmission. Use a spark plug gap blades tool used for measuring the gap and rotate the shaft and test the gap between the coupling and transmission coupling plate. The gap should be within 0.001" of each other. If it is not the same then engine re-alignment is needed. It is beyond the scope of this space to describe how to align the engine - You may consider hiring a mechanic for that.
 

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Chachere
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[quote=newguy]Assuming you replaced your mounts because of excessive vibration.  If so, did replacing them meet your expectations[/quote]
I replaced the mounts because the surveyor (when we bought the boat  6 years ago) told us they were due to be replaced.   Since I had barely used the boat before doing this (and I did the work over the off season), I really didn't have much of a baseline of experience to compare vibration before vs after.    I used the Vetus K75 mounts, on Tom Soko's suggestion.

[quote=Talisman]How do you align the engine or even know if it is misaligned?
 [/quote]
   I just searched and found my thread from 6 years ago, when I had the same question (and got some good advice)! Its here:
www.catalina36.org/forum/technical-discussion/engine-alignment-after-mount-replacement
(Note that there is a reference in there from Gary Bain, directing to page 41 of the C36 owners manual; that link has changed and now can be found at  www.catalina36.org/sites/default/files/legacy/C36MkI_Owners_Manual.pdf  ).
   In any event, more detailed write-ups can be found in Don Casey's "This Old Boat" (in the 2d edition  at pp 179-183) or Nigel Calder's "Boatowner's Mechanical and Electrical Manual" (my copy is on the boat at the moment), with illustrated instructions on how to check alignment, so I suggest consulting either (or both) of those useful books.  (To me, essential books for the libraries of amateurs like many of us). 
   I'd add that if your boat is hauled for the winter, you can (and should) check outside where the prop shaft enters the tube (known as the "shaft log") -- it should be centered and not touching the shaft tube at all (if it is touching, and you don't rectify by adjusting the engine mounts, you can look forward to a nasty repair job on the shaft log tube at some point!). 

 
 

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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GaryB
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Posts: 570

Matthew,
I checked when I read your comment about the manuals not being on the website. In checking it is still there under members/ technical articles / manuals pgs 40-43 for MKl and pgs 45-48 for MKll. Both manuals are located in the C36 Manuals.
https://www.catalina36.org/members/technical/manuals?page=1

Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine

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Chachere
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Posts: 825

[quote=GaryB] Matthew,
I checked when I read your comment about the manuals not being on the website. In checking it is still there under members/ technical articles / manuals pgs 40-43 for MKl and pgs 45-48 for MKll. Both manuals are located in the C36 Manuals.
https://www.catalina36.org/members/technical/manuals?page=1 [/quote]

Thanks, Gary.
That link to the manual in your posting from 6 years ago in the thread I referenced to above didn't work, I guess, not just because it referred to "c36ia.com" (that would probably forward to our current site name), but because it referred to a file folder location that no longer exists after the site was reorganized a few years ago.  (Not the first time this has happened, I'm sure).

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

Talisman
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Joined: 12/26/07
Posts: 243

Thank you all

Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
 

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pkeyser
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Posts: 659

Enrique-
Clarification to the spark plug feeler gauge comment above-
The gap should be checked with the boat in the water and mast rigged. If you do this on the hard (and even worse- realign the engine when the boat is on the hard) - everything will be off because of the hull flexing vs. its shape in the water. Been there and done it.

Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B

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