Universal M25-XP Broken Engine Mount L Bracket

[Ward H]

Good Evening,
My 93 C30 has the Universal M25-XP.
When I bought it in Nov 2017 the PO was in the process of having the front starboard L Bracket replaced with one built by a machine shop. He had lost half of the broken L bracket and had a machine shop copy the port side mount. The L bracket bolts to the block with 4 bolts and connects to the engine mount itself.

My surveyor was aware of this, inspected the new bracket and observed the running engine during the water survey. He said this was not an uncommon problem on these engines and he didn't see a problem with the replacement bracket.
I did have the engine/shaft alignment redone once in the water in 2018.

I searched for info on-line and found one person who posted about his broken L bracket in 2012. He had a quote of $200 for one bracket by a Universal parts supplier and instead had 2 made up out of 1/4" SS for $120. There was no follow up posts about the bracket.

Today I found the replacement bracket broken in the exact same place as the original. (Somewhere I have the remaining half of the original mount). I asked the yard owner and he said it was common and they had redesigned the bracket to be stronger. He was confident he could source the part.

It appears the bracket "tongue" that the engine mount bolts to is weak and engine torque stresses it causing a stress fracture. Photos attached.

I have no clue when it happened. Last season I did not notice any unusual vibration.
In 2019 I did start getting a singing noise at certain RPMs and speeds. Using a stethoscope it appeared the noise was coming from under the cockpit. I asked on various forums, a few mechanics and most thought it was a harmonic noise nicknamed a singing prop. My local prop shop explained what caused a singing prop and said while it was more common on go fast boats, the symptoms pointed to it.

My question for the group is this:
Is having this bracket breaking actually common?
Could I have actually motored about 80 hours last season and not noticed anything out of the ordinary except for the strange singing noise?
Does it make sense to have beefier brackets built by a machine shop?

Thanks for any thoughts or suggestions.

Just remembered I did have an anchor line wrap the prop shaft about mid season last year. It pulled tight and shut down the engine. Could that caused enough engine torque to break the bracket?

 

[Michael Davis]

Just remembered I did have an anchor line wrap the prop shaft about mid season last year. It pulled tight and shut down the engine.

At what RPM Ward? There is a lot of torque in a Diesel engine. Not fussy about the design of that bracket. The end of that gusset will always be a weak point. “U” channel with the gusset would be a lot stronger but you’d need a socket to adjust your alinement.

 

[Stu Jackson]

Is having this bracket breaking actually common?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Just remembered I did have an anchor line wrap the prop shaft about mid season last year. It pulled tight and shut down the engine. Could that caused enough engine torque to break the bracket?

Ward, so sorry to hear.

1. No. Because you know I'd have heard about it.

2. Could be, given your helpful and detailed backstory.

When I firast read through it, my first thought was "gusset plate" but see you had one. Thickness of horizontal plate would be first guess, or need for gussett(s) on the top, too. I'm not an expert on welds, but that one looks more like JBWeld than a real one...

Good luck.

 

[Ward H]

At what RPM Ward?

Under 1500rpm. We were moving slowly around the anchorage when the wind pushed us over our line.

 

[Ward H]

Ward, so sorry to hear.

1. No. Because you know I'd have heard about it.

2. Could be, given your helpful and detailed backstory.

When I firast read through it, my first thought was "gusset plate" but see you had one. Thickness of horizontal plate would be first guess, or need for gussett(s) on the top, too. I'm not an expert on welds, but that one looks more like JBWeld than a real one...

Good luck.

Yeah, if this was common I figured you would have heard about it.

I’m thinking the length of the horizontal piece that is unsupported by the gusset, is too long and too thin.

 

[dlochner]

I’m thinking the length of the horizontal piece that is unsupported by the gusset, is too long and too thin.

That would be my first thought too. Is this SS? Different metals have different characteristics, SS is susceptible to stress hardening which can make it brittle. Before replacing some metallurgical research may be in order.

The weld looks fine to my eye, nice and even.

 

[RoyS]

I would try 3/8" stock on the broken leg. No need for stainless steel either, just paint. Mysterious.

 

[RoyS]

Just had another thought. It is possible to align the engine to the shaft but have the engine unevenly supported on its four mounts. One or two engine mounts could be unloaded with the engine supported entirely by the other two or three mounts. If this is the case here then that broken mount may have been the sole support on that end of the engine and may have been overloaded beyond its capacity in the line wrap incident. When the engine is aligned to the shaft care must be taken to equally load all four engine mounts. Just a thought.

 

[dmax]

Stu, you're slipping (though it was a long time ago) - here's a thread on c34.org describing the same problem, Universal issued a service bulletin, apparently the cure is to build one with a larger gusset. Mentions that it broke when a line went around the prop:

broken engine mount

broken engine mount

c34.org

 

[Ward H]

Stu, you're slipping (though it was a long time ago) - here's a thread on c34.org describing the same problem, Universal issued a service bulletin, apparently the cure is to build one with a larger gusset. Mentions that it broke when a line went around the prop:

broken engine mount

broken engine mount

c34.org

Wow, thanks for this post. And in the last post in that thread, was dated Nov 1, 2019, the poster stated his bracket broke when a line wrapped on a prop. Probably what drove mine to the breaking point.

Now to find the bracket.

 

[Ward H]

@weekendrken just posted about the service bulletin over on the C30 site. Many thanks to all.

 

[Stu Jackson]

Stu, you're slipping (though it was a long time ago) - here's a thread on c34.org describing the same problem, Universal issued a service bulletin, apparently the cure is to build one with a larger gusset. Mentions that it broke when a line went around the prop:

broken engine mount

broken engine mount

c34.org

dmax, I take some (rather than great) umbrage at what is a particularly incorrect and incomplete evaluation of that thread you linked to.

Why? Because as I so often do on our C34 Forum, I linked it to a further evaluation by Ron Hill, The Guru of our C34s. He added yet a second thread to that topic as a distinct followup. I linked it in the next to last post on that topic, reply #18, in 2007 (the last post on that thread is in 2019 from a new owner who had just "discovered" the thread).

My link to Ron's followup is this:
"This goes to: Re Visit - Cracked Engine Mount Brackets "

Ron's post reads:

Thought I'd start a new thread.
I thought it strange that I hadn't heard about this problem on the M25XP engine before. I had heard that the M35Aengine had some cracked engine mount problems - a friend had one. The pictures in that post were from a M35A engine.

Rick sent me a copy of the Westerbeke Service bulletin #214 (17 May 1994) which outlined the problem which I thank him for. The key is in Westerbeke's wording that "fracturing across the bracket just forward of where the lower support gusset for the bracket terminates." The M25XPAengine has NO gussets on their engine mount brackets!! I checked 5 M25XP"A" engines and my parts manual, and found NO gussets (the 45 degree support bracket welded on the underside). The M25XPA engines appear to have a "thicker" bracket.

I believe that the problem is isolated to the M25XPB engine (26hp) and the M35A engines (30hp). The M25XPB engines were installed in the later C30s while the M35A engines were limited to the early 1990s C34 & C36 Catalina's.

Always inspect your engine mount brackets, but my limited research indicates that the Front Mount Cracking Bulletin is not referring to the M25XPA engines in the C34s!!

My recollection was valid. Few C34s had M25XPB engines, very few, and many of those who did were repowers.

Doesn't mitigate Ward's issue, but those are the facts. And why I didn't hear of a lot of them on M25XP engines. (Note: M25XPA engines are M25XP engines, in common terms. The M25XPB engines are different machines.]

Partial quotes are as bad as those taken out of context. Slipping? Hardly...

Your boat, your choice.

@weekendrken just posted about the service bulletin over on the C30 site. Many thanks to all.

Ward, our C34 Critical Upgrades topic has included "Check engine service bulletins" since 2009!!! CRITICAL UPGRADES - DO THESE OR ELSE!!!
Ken's late to the party.

 

[dmax]

Sorry Stu, it was in jest - you are an encylcopedia of knowledge and no, you're not slipping. I had remembered reading about a broken mount and found the article - I think it applies to Ward's situation even though it's not quite the same engine. Admittedly, I didn't follow your link to Ron's post. I really respect your opinion and have been reading your posts for more than 15 years and have learned a lot. I'm glad it was only "some" umbrage

 

[dLj]

Let me preface this with I don't have a clue about you particular boat/engine/mounts.

Looking at the pictures there are a couple things that jump out at me. The first is the underside of the break at the junction of the gusset to the unsupported end where the weld wraps around the front of the gusset. Almost looks like there may have been an original weld defect that could easily have initiated a fatigue crack running along that fracture surface. Can't really tell from the photos you've posted, I'd have to examine the fracture surface.

Before I'd start going down the road if redesigning the bracket, I'd want to know if that was the case.

@Ward H you live close enough to me, want to bring your bracket over and take a look?

dj

 

[Ward H]

Sorry Stu, it was in jest - you are an encylcopedia of knowledge and no, you're not slipping. I had remembered reading about a broken mount and found the article - I think it applies to Ward's situation even though it's not quite the same engine. Admittedly, I didn't follow your link to Ron's post. I really respect your opinion and have been reading your posts for more than 15 years and have learned a lot. I'm glad it was only "some" umbrage

Yep, that thread did help as it has photos of the M25-XP broken bracket as well as a M35 broken motor bracket and it listed SB 214. (Those two engine models are the subject of SB 214.) Much of that thread does talk about M25-XPA and M25-XPB and M35B which confuses the issue but thanks to everyone's help I did find the Westerbeke site and the SBs for my engine.

Stu, Yep I've read your Critical Upgrades in detail several times and made sure I followed those my engine needed but this one I missed.

Many Thanks to All.

 

[Ward H]

Let me preface this with I don't have a clue about you particular boat/engine/mounts.

Looking at the pictures there are a couple things that jump out at me. The first is the underside of the break at the junction of the gusset to the unsupported end where the weld wraps around the front of the gusset. Almost looks like there may have been an original weld defect that could easily have initiated a fatigue crack running along that fracture surface. Can't really tell from the photos you've posted, I'd have to examine the fracture surface.

Before I'd start going down the road if redesigning the bracket, I'd want to know if that was the case.

@Ward H you live close enough to me, want to bring your bracket over and take a look?

dj

I'd take you up on that offer Dave but it's about a 2.5 hour drive 1 way. The WB Service Bulletin identified the issue and the fix that they applied to their replacement brackets. (They extended the gusset 1 1/2" inches to reduce flex of the horizontal piece)
If I didn't have the SB that identified the problem, it would be worth the drive. I have no expertise at all with welding.

 

[Stu Jackson]

I'm glad it was only "some" umbrage

Thanks much, dmax, much appreciated. I'm glad I put it that way, too!

 

[dLj]

I'd take you up on that offer Dave but it's about a 2.5 hour drive 1 way. The WB Service Bulletin identified the issue and the fix that they applied to their replacement brackets. (They extended the gusset 1 1/2" inches to reduce flex of the horizontal piece)
If I didn't have the SB that identified the problem, it would be worth the drive. I have no expertise at all with welding.

What's a little 2 1/2 hour drive .... jeeze.... (I actually thought we lived closer)... And another excuse to meet up with you is shot down... dang...

dj

 

[Stu Jackson]

And another excuse to meet up with you is shot down... dang...

I know how you feel. Ward came all the way to British Columbia, and I missed him!!!

It had something to do with a February snowstorm, unique I know and so unexpected, but still...

 

[Michael Davis]

What's a little 2 1/2 hour drive ..

Driven further than that for a cup of coffee......