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Transmission Replacement

Feb 2, 2013
31
Catalina 310 282 Bluewater Bay
ALL
Replaced the ZF5 Hurth with a PRM60 with new Damper plate on WHITS END hull #282. Prior to replacement had a bad vibe at idle <900 rpm so had turned up idle to 1100 for smooth running. Now bad vibe is even more pronounced at 1100-1400!
I removed, cleaned, painted engine mounts and realigned engine to < .003". Cutlass bearing is 4 yrs old. Prop and hull clean.
I understand that 3 cyl universal engine has a harmonic vibe that can transmit to hull via mounts.
Anyone had similar experience? Can moving engine mounts slightly change Harmonic?
 

BillyK

.
Jan 24, 2010
382
Catalina 310 Ocean City, NJ
I'll find out in the spring if i'll have this experience.. i installed a new shaft, cutlass, realigned prop, new engine mounts, new shaft colar, new damper plate and a pss seal..

how old are the engine mounts? do they sag? were they deformed when you had them out to clean/paint? mine were visibly out of alignment when just sitting on my workbench.. you can see my little adventure on this Here. how many hours are on the engine? ever adjust the valves on it? quality of fuel? check the spark plugs? (kidding)..
 
Feb 2, 2013
31
Catalina 310 282 Bluewater Bay
504 hrs. No valve adjustment. Fuel clean. Engine starts immediately and runs great except for pronounced vibration at 1100-1400 rpm.
 

JRT

.
Feb 14, 2017
1,626
Catalina 310 211 RoseLeigh Lake Guntersville, AL
Is it correct to assume the salt water environment has a bigger impact to causing issues like new transmissions and mounts? All my limited ownership has been fresh water and my 2003 has been 100% fresh water since new, and this is my first internal motor sailboat/power boat. I've checked the mounts and they seem fine, vibration isn't concerning when I adjusted to the recommend idle, and others more experienced sailors say my motor and transmission are great. I go slow leaving and really don't tax it unless we have a storm moving in and I want to get off the lake. I know the first owner was very active in his use of the boat, and had it hauled each winter and logged PM very consistently. The second owner took equal care and did some very professional upgrades but his use of the boat was less so she sat at the dock a lot more.
 
Feb 2, 2013
31
Catalina 310 282 Bluewater Bay
Unless you get water in your boat on the engine, fresh vs salt should not make a difference. Salt is much more corrosive than fresh water, but for interior boat parts, I have not seen salt being an issue. It will corrode seawater water pumps, fittings, etc.
 
Feb 8, 2014
1,118
Columbia 36 Muskegon
I doubt salt water had anything to do with having to replace the Hurth transmission. It likely failed just because it's a Hurth. They fail in fresh water too, they're junk. The PRM is a much better unit and a drop in replacement.
 
Dec 25, 2008
1,519
catalina 310 Elk River
You stole my name..Ha Ha. good choice though. My previous boat was the "Kinky Turtle" had lots of fun with that one.
So regarding the vibration problem, in gear our out? these 3 cyc diesels with light flywheels are know to have this problem. If your mounts are adjusted near the top, consider chocking them up, that will stiffen thing up a bit.
 
Dec 25, 2008
1,519
catalina 310 Elk River
Your not going to change the relative position of the engine to the boat by doing this, only dropping the location of the engine relative to the mount. By raising the bottom of the mount the bottom nut on the mount screw will be 3/4 lower, less torque on the mount, less movement....less vibration.
 
Feb 20, 2011
7,197
Island Packet 35 Tucson, AZ/San Carlos, MX
Your not going to change the relative position of the engine to the boat by doing this, only dropping the location of the engine relative to the mount. By raising the bottom of the mount the bottom nut on the mount screw will be 3/4 lower, less torque on the mount, less movement....less vibration.
I get it. Thanks.
 
Dec 25, 2008
1,519
catalina 310 Elk River
You know it just occurred to me your problem with the increased vibration may have to do with the new damper plate. If your damper is too stiff it can't smooth out torsional vibration properly. What plate did you use? A number of the members here have replaced with the sacs 1866 061 001, I used 1866--50-002 as it was softer and rated properly for the torque output of the MX25.
 
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