How Loud is Your M25

Stu Jackson · Oct 21, 2012

Three things I've found that the internet is useless for:

sounds, smells and electrical without a wiring diagram.

rpwillia · Oct 21, 2012

Stew, You missed pictures ...

but for this post it is spot on. I have noticed my neighbors 309 with a Yanmar is a lot quieter. My boat has a lot of rattles. Last year when I replaced the old R&D damper plate with a Sachs it got noticeably louder. Most of it is vibration related (both in and out of gear) and is just plain annoying. :cussing:

Ralph Johnstone · Oct 21, 2012

Have You Noticed . .....................................

........................ that the exhaust outlet on the Hunter 310 is underwater. This may account for the reduced noise. Some of the others you mention may have the same lay out.

Because mine is so quiet, I have no problem in sneaking up on submarines

.

anchorclanker · Oct 21, 2012

Vibration accentuates sound. Bad motor mounts, engine to prop shaft misalignment, whacked prop, will all magnify the engines normal sounds and vibration. Imagine a combination of the three working together and you could have a veritable mariachi band. State of tune also, and exhaust as mentioned. But every boats going to be different too, and if your engine compartment isnt soundproofed as well, well......

Witzend · Oct 22, 2012

Stu Jackson said:
Three things I've found that the internet is useless for:

sounds, smells and electrical without a wiring diagram.

The poster would need to get a microphone and/or a DB meter, and Stu needs to get a set of speakers for his computer.

Yea it's a trade off like anything else, we have the access baby thought!
I don't spend anytime in the cabin while running, at the helm mostly so it is not a issue for me. Tunings thing up will help though.

So RP since you replaced you damper it got louder..do I have this correct?
Mine is much quieter. I used a different Sachs plate (1866--50-002) than you did if I recall?

FYI from some time ago.
Maine Sail 11-17-2009 03:15 pm Witz,

I just made a call to the distributor who ships the engines to Catalina and whom I get my Universal/Westerbeke parts through.

The R&D damper plate was stock, and factory, however according to the distributor "We had nothing but problems with them and most of them failed and some caused more damage than good"

I never knew Universal used anything but Sachs but apparently they did try some R&D's...

The spline fit was most likely spot on but as it failed it began to eat at the splines. The replacement Universal/Sachs damper plate is a Universal part number U-299156. I had them pull it off the shelf and read me the part numbers. The Sachs number is a 1866-050-002.

Maine Sail · Oct 22, 2012

Universal & Westerbeke use harder mounts than Yanmar. Yanmar's need the soft mounts to help control idle vibrations where the Universal/Kubota's and Westerbeke/Mitsubishi engines don't need as soft a mount. The soft mount helps to isolate transmitted vibrations through the engine stringers and into the rest of the boat. Proper alignment, good mounts and sa good running engine will make these engines fairly quiet & smooth but I doubt you'd see one as "quiet" installed as a Yanmar due to the mounts. The nice thing about the Universal & Westerbeke mounts is that when motor sailing you don't throw your alignment off as badly. The Yanmars tend to twist off easier and result in more shaft whip when motor sailing.

Everything is a trade off. You would NOT want a Yanmar with Westebeke/Universal style mounts, TRUST ME!!!

mfarinas · Oct 22, 2012

gpd955 said:
I moved a bunch of boats, variety of sizes and models, to their winter locations this week. I noticed that, for the most part, the engines are quiet. While I was motoring my own to her winter home this year I found that it is much louder in the cockpit of my 310 than it is in the cockpit of the Irwin 30 or Hunter 310 and 410. All Yanmars I believe. I've just attributed it to the fact our engines are just sitting in the open while theirs are all snuggled away with wood all around (except the Irwin).

The noises aren't unusual sounds just higher volume in comparison. The one banging sound at mid-RPM's that i had in the past was identified and solved. The soundproofing material on the engine cover is the original.

Just want to know if other 310 owners think the same about theirs.

Is it obvious that my boat is on the hard??!!

I also had considerable noise with my M25, especially at idle speed. Most of the noise was vibration related. Certainly a fouled propeller will increase the vibration.
I was able to reduce the very uncomfortable vibration at low RPMs by using bio-diesel in my fuel. The idle speed has now been reduced to 950 RPMs and the engines sounds much, much better.
I have been using bio-diesel now for almost 80 hours of engine running time. The mixture of bio-diesel to petro-diesel was slowly increased from 5% to the actual mixture of 15% right now.
You might want to try some bio-diesel and see what results you get.
I have not seen any detrimental effects as of now.

Witzend · Oct 22, 2012

One of the things that can be done to limit vibration is: if your engine mounts are near the top of their adjustment, block them up. This reduces the torque and lateral movement applied to the mount. The front ones are most affected. An easy fix!

rpwillia · Nov 5, 2012

Engine db measurements

I ordered some new engine mounts. I wound up going with the

MM-Small-65 rubber - $35.00/each + M12 height adjuster $12.00 from avproductsinc.com, http://www.anti-vibration-mounts.net/MM1.pdf

One minor issue is the holes are 4" on center, where the old ones were 5" on center. Since I am going to re-install the shaft flex coupling which pushes things back about 1" it is almost a wash.

In preparation for replacing the mounts I decided to take some measurements with a db reading app on my android phone (hey it was free). Below are the measurements.

Old Engine Mounts
RPMs 0 1000 1300 1550 2500
Cabin 39.2 87.7 76.7 82.8 88.3
Cockpit 55 84.7 68.5 76.7 80.7
Cockpit - Cover Open 55 84.9 77.5 81.8 90.9
Cabin - Cover Open 39.2 92.2 93.4 94.9 93.1

When I get the job done I will post the updated noise values.

pk104 · Nov 6, 2012

Hey thanks for the app. I just downloaded it and works great. I will resist testing commercials and getting more upset then I already do when the volume goes up.

rpwillia · Nov 6, 2012

Picture of the motor mounts

NT

anchorclanker · Nov 6, 2012

DO NOT disregard witzends suggestion.

degreeoff · Nov 7, 2012

Not to mention the fact that spacers will stiffen the area with the mount bolts for those of us who have had rot from the water or oil over the years......... I'm doing that asap! Replaced my mounts, still loud as hell.

paulj · Nov 8, 2012

Stu Jackson said:
Three things I've found that the internet is useless for:

sounds, smells and electrical without a wiring diagram.

On the way home, Sunday, I saw these sailboats on San Francisco Bay......and a cluncky sound comming from one sail boat.

I think it was a Catalina 34 with a M25 engine.........I know because I'm in the know.......1st thing came to mind was .......is that Stu ?

paulj :troll:

Stu Jackson · Nov 8, 2012

Nope, but if you'd have looked down and to your left, that little marina has my favorite anchorage.

Yup, we do that thunkity thing every once in a while. Lets me know the engine is running.

rpwillia · Nov 10, 2012

What is in the stringers

I am doing the prep for pulling the engine up and replacing the mounts and pulled one of the boats that holds the motor mount to the stringer and it is machine threaded. So has anyone changes these? I was under the assumption they would be some kind of lag boat that I could just drill a new hole to accommodate the different spacing (4" vs 5") on the new mounts.

Witzend · Nov 10, 2012

Wrong Bammp, These morons have installed SS bolts into Aluminum blocks. Can you spell Corrosion! Two of mine twisted off even after 2 hours of working on then with an impact wrench and PB blaster. Of course they were the port rear ones with the worst access. Must drill and tap new holes. Put lithium grease on them before you put them back in again, so the next sucker can get them out when your new mounts eventually fail.

rpwillia · Nov 11, 2012

Thanks

Better that what I was fearing. A Pearson owner told me his had bolts on the back and I was wondering, if that was the case, how I would get to them. The aluminum plate makes a bit more sense and is consistent with what Catalina usually does.

How Loud is Your M25

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