New Motor Mounts for an Ericson 32-3 & M-25

[vanilladuck]

Part of Rumour's "half-life refit" is considering new motor mounts. The mounts on the boat now are completely rusted over and will probably take quite a bit of PB Blaster and Kroil to break free. There doesn't seem to be a ton of vibration, but I've never known different on this boat. The rubber is likely pretty degraded.

I did some searchin' and found some older threads about motor mount replacements on E32's. Here's what I found for reference:

Motor Mount replacement: M25XP

We are about to do some serious fall maint. and one of things on the list is reducing the vibration from the engine. My contact at the boat yard advises that 18 years and 1700 hours of run time would indicate that the original mounts are hardened and no longer doing much to dampen vibrations...

ericsonyachts.org

Engine mount recommendations

I am replacing the engine mounts on my 32-3. The 32-3 uses three mounts. Does anyone have any recommendation for brand and type. I see a lot of different options, some are a bit pricey like the vetus hydro dampener that claim "the reduction of vibration and noise is truly staggering"...

ericsonyachts.org

Stripped holes in engine mount stringers...

Hello All, Had the engine hoisted back in again only to find that the three holes I tried putting the lag screws in were completely stripped. I'm more than a little pissed right now as lag screws are a poor idea in the first place to hold the engine mounts down for a few reasons. Lag screws...

ericsonyachts.org

Motor Mounts Reduce Vibration?-Yep

Thought this might be of interest to someone. Recently, when I had the engine (M25 Universal) in our 86 E32-3 hoisted up (I built a nifty hoisting jig out of 2 X 4s and turnbuckles) to remove my transmission for rebuild I also replaced the Motor Mounts. I chose “Thermoboat” brand which the...

ericsonyachts.org

I asked AI to compare the top three suggestions from those threads:

• PYI R&D Mounts
• Vetus K75 Mounts
• Poly Flex Mounts (no link)

Here are the results: https://docs.google.com/document/d/...Z7eSQGuujEY0VXRfylGJPBViz1Pf4x_9X_JiVXROk/pub

Even before I asked AI, I was concerned about the three (3) mounts on the E32-3 instead of four (4). That puts a lot of reliance on the forward mount.

Has anyone else updated their motor mounts on the E32-3 with an M-25 engine? What's the going recommendation?

 

[bigd14]

Post in thread 'M25xp, convert from 3 point mount to 4?'
https://ericsonyachts.org/ie/threads/m25xp-convert-from-3-point-mount-to-4.14647/post-106217

I had some custom brackets fabricated to convert the forward single mount to doubles and went with hanger bolts epoxied into the stringers. Details in the post above. It’s for an M18 buts it’s the same engine as the 25 minus a cylinder so the bracket design should still work.

 

[JSM]

Even before I asked AI, I was concerned about the three (3) mounts on the E32-3 instead of four (4). That puts a lot of reliance on the forward mount.

Has anyone else updated their motor mounts on the E32-3 with an M-25 engine? What's the going recommendation?

Switched over to four mounts using the existing bracket on the front of the engine, got rid of the lag bolts for the rear mounts by using steel plates with nuts welded to the underside so that the mounts could be held in place with machine screws. The plates are secured to the engine bearers with lag bolts.
Went with the Vetus K75 mounts and have been very happy with them .

 

[vanilladuck]

Thanks @JSM and @bigd14 -- I'm very curious about moving to four mounts. I'm heading down to the boat today to get an idea if this is possible based on engine height and stringer positioning around the engine well. If there are any E32-3 owners who replaced their motor mounts, I'd love to know what you did and reasoning around it

 

[vanilladuck]

Just getting back to this...



I'm trying to think of how I could adapt the current engine bay for the two front mounting points on the engine block (shown with pink arrows above). The two mounts are hovering over the engine bilge inboard of the stringers that support the rear mounts.

I suppose I could build some FRP or G10 mounts and bolt them to the stringers, but the lever arm it would create on both sides would seem to be a bit janky. Also, I can currently get my arm into the engine well/bilge to clean, replace the absorbent mat, etc. Building more structure in this area would seem to prohibit such access.

Curious if anyone has converted their 32-3 to four mounts...

 

[vanilladuck]

Thanks to a PM from @Norwester, I saw this post from Capt Ian re: his E32-3:

M25xp, convert from 3 point mount to 4?

While eyeballing Beta Marine engines at the Chicago Boat Show this weekend I mentioned to the rep my problems with trying to vanquish vibration at certain RPM with the M25xp on my E34. He claimed that the largest cause of vibration problems associated with this engine is due to the 3 point...

ericsonyachts.org

I think that is an M-25XP engine a not a M-25, like on Rumour. Seems like the front side mounts were left off the 25XP?

 

[Dave G.]

Can't really tell how much space is between the current front mount plate and the stringers but if there's room Why not bolt(or weld) a longer 1/4" plate under the front mount plate and put 2 mounts at the ends ? Think you could still have access to the well.

 

[Loren Beach]

Our boat was built with the Universal M25XP engine, and had four mounts. I sort of recall that the front mounts are bolted to the block, but I have not seen that engine since we repowered in 2018. My surmise is that when EY ordered engines with a single mount on the front, the vendor saluted and provided them - by the truck load...

 

[JSM]

I think that is an M-25XP engine a not a M-25, like on Rumour. Seems like the front side mounts were left off the 25XP?

The M25xp on my 34-2 came from the factory with three mounts. I converted it to four. I was a bit unsure if this would work until I noticed on the M25/M25xp parts diagram that the bracket for the front mount is listed as the "3 and 4 point combination mount".
Converting it to four point and using the Vetus mounts eliminated most of the vibration problem I was having.
Two years later I installed a new Twin Disc gear and damper plate and vibration is now almost non existent.

 

[Pete the Cat]

This is an interesting issue. I have had some discussion with the engineers at Yanmar about their weird (unique) engine mounts and the characteristic shaking most of the Yanmars seem to do at idle because of the motor mount design compared to other engines I have worked on. The engineers say that Yanmar made a conscious choice to keep the engine vibration in the engine and not transferring the vibration and noise to the hull, bed and drive train. They said that a properly aligned engine can vibrate and it is better for the entire drive train to do so than to strap it down to the bed so that it transfers elsewhere. This was from a couple engineers at a Yanmar show several years ago. Not sure if they were scientifically correct, but there is definitely a very big difference with the way Yanmar designs its motor mounts and these were not just salesmen at the show. FWIW; I was checking the alignment on my 25XP (3 mount) and found the lag bolts a bit loose, though the coupling appeared to be in perfect (!) alignment. FWIW.

 

[Frank Langer]

Ray,
I pay alot of attention to the alignment on our boat, but noticed that one of the lag bolts was a bit loose. It's in a location where I would have to lift the engine to remove/ replace the bolt, which I was unwilling to do. As the engine alignment was perfect, I decided to add a filet of epoxy around each motor mount to "secure" them to the base stringers. That was several years ago, and the alignment continues to be perfect, so I think securing the the motor mounts has helped alot. If I ever have to replace the motor mounts, some work with a chisel will likely free them.
Frank

 

[Loren Beach]

FWIW; I was checking the alignment on my 25XP (3 mount) and found the lag bolts a bit loose,

To this point, I used to have to (slightly) torque most of the large lag bolts on the four mounts on our prior Universal. It seemed that even though threaded into heavy frp moldings, into hardwood, they would loosen due to vibration. This was done about every other year. This did kind of make me wonder if the earlier generation of Kubota had more vibration than current iterations of those engines. Since these engines were sold into a relatively small niche market for marine use, one wonders if vibration (below a certain point) was considered a problem to further solve for use in tractors or on skids/frames for stationary power?
To my uneducated eye, our newer (Kubota) Betamarine seems to shake less.

 

[bigd14]

found the lag bolts a bit loose

I used hanger bolts (half lag screw, have machine bolt) epoxied into the engine beds to alleviate this issue. Adjustments can then be made using the nuts on the machine screw threads without loosening the lag bolt ends. So far so good after 9 years.