Hunter 29.5 2GM engine vibration

[BigEasy]

Ralph,
I can't explain the discrepancy between the Yanmar & Ellebogen mount recommendations (fore / aft placement).
I can verify, with certainty, that the original Yanmar (3YM30) mounts installed at the Beneteau factory were 100 shore rating installed forward & 75 shore rating installed aft. Just verify for your application when you remove old mounts.
A few tips for this job:
Disconnect transmission flange & shaft coupling. Support shaft with scrap lumber.
Loosen top locking nuts on mounts.
Mark position of existing mounts on FRP stringers.
Place scissor type jack under engine with wood buffer between jack & oil pan. Do not have to raise engine, just support.
Remove nuts/bolts from base of engine mount.
Remove bolts that attach mounts to bracket on side of engine & slide mount & bracket assembly out horizontally.
Set new bracket slightly higher than old mount. Note position of slot in old mount. Slide back into place & secure bracket / mount
assembly to side of engine.
Super glue fender washer & nyloc nut together & place into box end wrench to ease installation of bolt & backing nut. Lubricate bolt.
Complete one mount before proceeding to next mount to minimize engine movement for easier alignment.
Remove jack & perform initial alignment, followed by fine tuning after a few days later, in water, to allow settling of new mounts.
Tighten lock nuts on top of engine mounts.
If access to the mounts & backing nuts is reasonable, this isn't a difficult job. If access is very limited, as in my case, it is a PIA.
One or two man job, again, depending on ease of access. I did this with boat in water. Good luck!

 

[BigEasy]

My good sir, I leave the positioning of motor mounts in your capable hands. Please don't leave me hanging .

Ralph,
See Ellebogen invoice in above post. I did not notice any difference in dimensions between the Yanmar & Ellebogen mounts; they appeared exactly the same.

 

[Brian M H23]

this was definitely my issue, all of them had rubber/metal separation and both starboard mounts had failed completely. I'm not sure how this guy was getting around, but the leaking gland and worn cutlass probably all caused by these failing.

Changed out the mounts yesterday. Really not a bad job, couple hours including re alignment. I didn't need to disconnect the shaft.

I ended up using these mounts in all 4 corners - This mount design is already quite compliant; it's hard to imagine putting 2 slightly softer ones in would make a huge difference. I'll let you all know when the boat shakes apart .

No time to get out on the water yesterday , but motor operation in gear against the dock lines was vastly improved. Getting there!

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[Brian M H23]

My good sir, I leave the positioning of motor mounts in your capable hands.

Based on specifications from both Ellebogen and Yanmar I offer the following :

View attachment 231533
Ellebogen


View attachment 231534
Yanmar Parts Catalogue



View attachment 231536
Purchase of Aft Starboard Mount in 2009
​

Check the parts numbers. My purchase in 2009 and the Yanmar parts catalogue show the same parts number. The Ellebogen parts numbers disagree. I am still looking for a paragraph in a Yanmar catalogue in which the Ellebogen and the Yanmar parts catalogue agree.

@BigEasy , I'm relying on you for the correct location of these mounts as I'm getting ready to replace the mounts on my 2GM20F with Ellebogen mounts next winter.

Please don't leave me hanging .

I came across the same discrepancy. The front mounts seem to be quite a bit more loaded than the rear, I would not put the soft ones forward despite yanmar and hunter documents that might suggest it.
I suspect the benefit of softer mount in rear makes the drivetrain more tolerant of misalignment, allowing the transmission to move around, or maybe some nuanced reduction in prop vibration to the hull.
I personally went with the 2gm20f(v) setup, 4x100, and can't imagine any significant downside, even though this isn't a vee drive. I certainly don't want it wiggling around even more than it can right now...

 

[Brian M H23]

Update all! Had a successful memorial day first outing. Motored out, sailed barnegat bay for a few hours. Some issues with the furling drum line jamming that a new line will fix, head only kind-of flushes. Expected kinks to work out on a new, used, boat.

As for the vibes

I don't have a good baseline on how much vibration is normal - but things were vastly improved from pre- engine mounts. Low rpm shakes a bit (motor - same idle or in gear), 1600-2100 under load purrs right along perfect, higher RPM feels like something coming synced prop or shaft (original 2 blade AFAIK, I didn't touch it) but nothing seriously concerning. The flex coupler did move the prop an inch farther away from the strut (but I needed to move the packing gland to a new, unworn place on the shaft, and the transmission flange had a little axial runout that the flex coupler makes a nonissue)

Tweaked the packing (3 rings of graphite /teflon) to get a tiny bit of water underway, no apparent leak with the shaft stopped. It's very sensitive; no wrench needed to completely stop the water. Assume that means I did a good job on my rings?? The whole inboard thing is new to me.

Cheers to a summer on the water (and learning a boat 3x as heavy as my old 23)

 

[Ralph Johnstone]

It's very sensitive; no wrench needed to completely stop the water. Assume that means I did a good job on my rings??

Right on the money. Gets a little stiffer as the corrosion grabs hold.

As spreviously mentioned, SEND US A VID. WITH THE ENGINE IN NEUTRAL and run from idle to 3600 RPM and we'll tell you what's causing your vibration.

If I get time, I'll send you a vid. of my 27 year old engine with original mounts. Minimum vibration. OCD is not all bad.

 

[Brian M H23]

Right on the money. Gets a little stiffer as the corrosion grabs hold.

As spreviously mentioned, SEND US A VID. WITH THE ENGINE IN NEUTRAL and run from idle to 3600 RPM and we'll tell you what's causing your vibration.

If I get time, I'll send you a vid. of my 27 year old engine with original mounts. Minimum vibration. OCD is not all bad.

Sorry, no video, but have gotten some sea time with the boat this summer. Engine purrs in neutral, no concerns there. Sailing in neutral, you can feel some vibration coming from the driveline as the shaft spins. The new mounts settled in and it could use a little tweak to the alignment, for sure.
I also realize I stuck a zinc on the prop shaft well away from the cutlass, which is apparently not good, especially if there's any bow in the shaft. Also completely unsure if the prob is well balanced; I didn't do anything at all to it, even clean it, before launch. To make the situation worse, this photo isn't even the final setup; I'm fairly certain with everything in place there's another inch of shaft (making it closer to 3" total) sticking behind the cutless before the prop; far too much overhang for a 2 blade prop on a 1 inch shaft..

 

[Brian M H23]

And just to make clear.. The reason I added a spacer in the coupling was to deal with two other issues, primarily that the cutless was beat, stuffing box was over tightened and wore a groove in the shaft. For a pre-launch job on a boat I bought end of season and didn't know much about (except that it leaked at the box), it's a huge improvement.

It's looking like a new shaft and maybe a feathering or folding prop may be in my future, though.

 

[Ralph Johnstone]

The reason I added a spacer in the coupling was to deal with two other issues,

Can you ad more detail to the spacer ? Maybe a pic.

 

[Tally Ho]

I replaced my shaft and coupling one year, but kept the traditional stuffing box. I did renew the stuffing box hose and repacked that year. The next year, I replaced the stuffing box with a Volvo dripless seal. I really like the Volvo seal and no water in the bilge.

I retired last year and bought myself a MaxProp 3-blade feathering prop. Wow…that is spectacular. Less vibration with the 3 blades, better light air sailing (added about 1/2 knot of speed), fantastic reverse bite, and adjustable pitch so I can really dial in my forward thrust to match my engine and how I motor. Expensive prop, but worth every penny in my mind.

A video about my Volvo seal…

Here is a little bit on my MaxProp. I installed something wrong the first time I put it on (my fault, not MaxProp). This is the day I did a short haul, and reinstalled it in the slings at my marina.

You don’t have to everything at once (expensive), but as you make improvements in your boat, you will get more and more enjoyment out of it.

Have fun on the journey.

Greg

 

[Brian M H23]

RD marine 4" flex coupler off ebay.
Easiest off the shelf solution, i probably could have shortened up the shaft log an inch instead but I already had the coupler and stuffing box installed before I realized my mistake.

Can you ad more detail to the spacer ? Maybe a pic.

 

[jssailem]

I stuck a zinc on the prop shaft well away from the cutlass, which is apparently not good,

Not necessarily. The zinc needs to be spaced so that water can get into the cutlass bearing to provide lubricant as the shaft turns.

 

[Ralph Johnstone]

Holy great snapping horny toads. If that collection of loose hardware doesn't contribute to your vibration problems, I'd be greatly surprised.

Yes, I know the manufacturer swore up and down that it would take away your misalignment problems forever but what if your original misalignment problem was way outside the capability of this amazing little Rube Goldberg contraption. In fact, how could you possibly even do an alignment check without the prop shaft flange in place ?

I'm sorry to add to add further pain and angst to your collection of problems at this point. It looks like you've been through the wringer (both forward and back) with what you've done so far but maybe it's time to throw in the towel and hand this job over to a "qualified" pro and have the enire prop shaft renewed and at least have your prop polished and balanced by a prop shop to allow yourself to take a breather. Be sure that your shaft is done by professional shop and not some wharf rat. Believe or not, they can make your problems even worse, far worse.

Use the boat as much as you can fore the remainder of the season and see what you really want in a prop. Check the archives here under props.

 

[Brian M H23]

Ralph,
The starting point here was completely thrashed everything. Motor mounts entirely disconnected so that the engine was leaping in the air, stuffing box leaking like a seive, huge amount of play in the cutlass. It's my first inboard boat. I asked the yard to do the cutlass back in November, by the time April rolled around they didn't even start.

I pulled the hub and shaft, cutlass done, new shaft log, put it back together, realized the stuffing box wasn't going to seal on the grooved shaft, tossed in that flex coupler and launched it, all in a week. I completely understand it's not ideal, but the alternative was getting into a whole new project. Haven't touched the setup since, just planning the next step.

I've got a perfectly serviceable boat with only the tiniest amount of leakage under power, very little time and money into fixing the issue, and now only some noticeable vibration that comes in at the top end of the power range (dramatically reduced since changing the mounts, which was the major problem)

The alignment is done by measurement of the change in gap between the two hub flanges with feeler gauges, at one fixed point, as you rotate through 360 degrees with everything bolted up. Definitely no idea what you mean about doing an alignment without the hub in place. It was pretty good at time of replacing mounts, though now with 2 months on the mounts it could surely use a tweak.

And not sure what warrants this response in general

Holy great snapping horny toads. If that collection of loose hardware doesn't contribute to your vibration problems, I'd be greatly surprised.

Yes, I know the manufacturer swore up and down that it would take away your misalignment problems forever but what if your original misalignment problem was way outside the capability of this amazing little Rube Goldberg contraption. In fact, how could you possibly even do an alignment check without the prop shaft flange in place ?

I'm sorry to add to add further pain and angst to your collection of problems at this point. It looks like you've been through the wringer (both forward and back) with what you've done so far but maybe it's time to throw in the towel and hand this job over to a "qualified" pro and have the enire prop shaft renewed and at least have your prop polished and balanced by a prop shop to allow yourself to take a breather. Be sure that your shaft is done by professional shop and not some wharf rat. Believe or not, they can make your problems even worse, far worse.

Use the boat as much as you can fore the remainder of the season and see what you really want in a prop. Check the archives here under props.

 

[jssailem]

realized the stuffing box wasn't going to seal on the grooved shaft

When I peeled back the stuffing box on my shiny shaft, I found the damage had been done over the past 9 years plus.

My first thought, well that is not too bad...
Then I opened up, and the rest of the story became evident.

Pitting corrosion on a 1 3/8 shaft.
My shaft was not leaking, but it was compromised.

It was time for this boat to get a new shaft, a trued shaft, and a new coupler that was "Faced and Fitted" to the shaft. The shaft was milled and prop fitted.
Took all the guesswork out of the equation. Once the engine/transmission was mated to the new shaft and coupler, the alignment went smoothly

 

[Ralph Johnstone]

And not sure what warrants this response in general

Sorry @Brian M H23. I did not mean to take away from the effort you've put into this project so far. You are to be congratulated on your effort but I'm sorry but I can't help but think that you would have been better off to take the more conventional approach and go for a new shaft when you have vibration which your spacer will not remove:

and now only some noticeable vibration that comes in at the top end of the power range

If it's bad, consider the transmission and what may be occuring inside. This is my only concern as far as rushing this job. You may cause further and more expensive damage than you now have. I certainly hope not.

As far as your alignment goes :

the change in gap between the two hub flanges with feeler gauges, at one fixed point, as you rotate through 360 degrees with everything bolted up.

I trust you meant to say "without" everything bolted up. This one step approach doesn't quite qualify as a shaft alignment. I've attached below the best instructional I've found to date on this subject

What each of us would do in a case like this is based on our opinion formed as a result of our experience over the years. You have yours, I have mine based on years of being around heavy equipment in industrial settings.

 

[Brian M H23]

Ralph thanks, that's a great resource.

I think we're on the same page here; keep in mind I didn't so much "choose" not to replace the shaft; deciding to pull the whole thing apart and change out the cutlass bearing on a new-to-me boat a week before launch was a lightning strike of insanity (was just going to refresh the packing).

A lot of the problems I now know were discovered in the water this year; a new shaft + eliminating the flex couping is definitely happening in the off season. This is probably a lesson in the value of getting a real survey more than anything, neglected driveline issue aside, 100% happy with the boat!

 

[Ralph Johnstone]

A lot of the problems I now know were discovered in the water this year; a new shaft + eliminating the flex couping is definitely happening in the off season.

If it's any consolation, you probably did a hell of a lot better than I could have if I'd been sitting here with the same boat you just bought. I took the easy way out and bought the boat new from Hunter back in 1998. No major problems (that I knew of) as soon as it splased after being commissioned. My inner knowledge of boats developed over the years as I did my own maintenance. I didn't learn squat about sailboats from being on a 42' C&C, 41' Hunter, and a 27' Catalina. Truth be told, none of the owners of those boats knew a water pump from a Water Pik. Not the kind of people you'd want to learn ANYTHING from other than how to drink, and drink, and lots more of that stuff.

You think you're happy with your boat now ? Wait until you've got everything exactly the way you want it and it just hums. Your boat is two years older and two feet shorter that mine but I think it's otherwise pretty well identical. If I can offer, do ALL of your own maintenance on the boat and never trust anyone. Amass a library of boat mechanics such as Nigel Calder's Boatowners Mechanical and Electrical Manual. In particular, get all of the Yanmar literature you can find related to your engine.

You're going to be thrilled out of your gourd the first time you come through some really rough water and then somehow (you've got the charts) finally find yourself in a protected anchorage with a good holding bottom for your anchor of choice (whatever the hell form that may take is up to you).