Hunter 326 - Yanmar Engine Vibration - New mounts and maybe more??
- Thread starter Breezy1
- Start date
Hate to rain on your parade but no, the prop shaft flange is checked for angularity, run out and the rest of the associated problems, in situ. Please see the below blurb starting at post #29. Also download the attachment on shaft alignment for a better understanding of what you're looking for.
Removing the Propeller Shaft Flange - H41AC
And what is the technique to press the shaft back into the flange? That I've never come to. Only seen it done in a plant maintenance shop with a very long press.
forums.sailboatowners.com
Maybe you can include your measurements as a check as to what's happening with your flange and shaft.
I see what you're saying, I tried to measure run-out but I wasn't totally prepared. The shaft moves quite a bit in the shaft log once it is disconnected from the coupling. I did take a video but it's too big to send, but a screen shot is attached and things look pretty square as I rotate the shaft. But again it can move quite a bit from side to side.
Also it is not totally in the center as you can see when it exits the boat in the other picture.
I printed the attachment for reading later.......
Attachments
Yes, reread what Ralph Johnstone said and find the source of the vibration without jumping all over the place. You will need to read up on how to properly check alignment, and how to check a cutlass bearing to begin with. You mentioned banging in your first post. This should be a pretty easy thing to find if it's from a bent shaft or big alignment problem just by lubing the cutlass with glycerin, rotating the shaft by hand in neutral and watching to see if the back of the engine moves up and down or side to side. The actual alignment is a pretty exacting process.
Also, considering the recommendation in your post, did a good marine mechanic already take a look at this and diagnose it for you? Is this person someone trusted in your area? If so, he's likely right in his diagnosis and nothing you do will likely change the facts.
Also, considering the recommendation in your post, did a good marine mechanic already take a look at this and diagnose it for you? Is this person someone trusted in your area? If so, he's likely right in his diagnosis and nothing you do will likely change the facts.
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Alignment should be done in water as the hull flexes when on the ground on stilts.
I have not had a mechanic look at it yet. I will likely put a dial indicator near the flange and then also outside the hull to see if there is anything grossly out of alignment or bent and this won't be too much work. I'll keep everyone posted.
While the shaft it out it is a very good idea to replace the cutlass because it is much easier with the shaft removed.
Most people think that a failed motor mount will be broken so that there is separation between the rubber and the steel. That is one form of break because the primary function is to connect the engine to the vehicle. If that was the only function, you might as well bolt the engine directly to the bed with steel shims for adjustment. But the mounts also have the secondary function of absorbing vibration which is the reason we use them instead of hard mounting. A motor mount will most commonly fail to perform this function before failing to hold the engine in place because the rubber in the mount work and age hardens over time and becomes too hard to absorb any vibration.
Before I replaced my motor mounts there was absolutely no movement in them when I would push or pull on the top of the engine and the mounts were completely rigid. The new mounts are much softer and allow the engine to shake rattle and roll at idle rather than just transferring all of that vibration straight to the hull.
My mounts aren't hardened as of yet. I can still shake the engine by hand. It was the horrible vibration and banging that resonated in the boat at about 1800 RMP that caused all this investigation. Lower or higher RPM didn't cause any issues. As a matter of fact it sounded as tho something was wrapped around the shaft and hitting the hull in a cyclical cadence.
In your "squareness" photo it appears that the gap is larger in the gap at the bottom of the photo than at the top. The gap, top and bottom - port and starboard need to be less than 0.003". It could just be an optical conclusion, but it does not look to be aligned to me.
Yes I know what you're saying - it does look that way, although it was difficult to take a pic at a good angle. I tried to get the light behind to see the gap however it is likely an illusion. Plus I could move the up and down, side to side as much as the shaft log would allow and that was slightly changing the angle as well..
On another note - I took a dial indicator and measured the runout of the center of the shaft as I rotated the prop and it was .020 (20 thousands) which probably is borderline. Shaft was mounted to the trans and in the cutlass. I'm going to pull the shaft and prop and have it checked. I'm thinking that may be the root cause of the vibration.
Weekend update: I was able to get the shaft coupling off as well as the prop so I can get everything checked and replace the cutlass bearing. I ran into a snag as I couldn't remove the shaft without dropping out the rudder. I kind of suspected but I was hoping I wouldn't have to. I didn't have the tools or the time to get into that, however before I do are there any tips or tricks??
Attached are pictures of the top-side. Looks like 4 socket head bolts and a pin. I don't see anything accessible from the topside rudder arm mount through the hull. It's about 30" of rudder post. Attached are pics of the topside access.
Attached are pictures of the top-side. Looks like 4 socket head bolts and a pin. I don't see anything accessible from the topside rudder arm mount through the hull. It's about 30" of rudder post. Attached are pics of the topside access.
Attachments
It might be possible, if you got the cutlass bearing out first , that you might be able to squeak the prop shaft past the rudder with the extra wiggle room. Just an idea. You would need to round up a puller. Is there a reason you have to remove the shaft in the first place anyhow? You can use a puller to remove and reinstall the cutlass with the shaft in place if you have a standard strut on the boat.
Edit: Never mind. I reread your posts above. You're committed to pulling the shaft. The biggest issue is you never isolated what the vibration problem was in the first place before you started disassembling things, so you might as well replace everything. You still could find issues with the damper plate or transmission, FWIW.
Edit: Never mind. I reread your posts above. You're committed to pulling the shaft. The biggest issue is you never isolated what the vibration problem was in the first place before you started disassembling things, so you might as well replace everything. You still could find issues with the damper plate or transmission, FWIW.
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First I would replace the motor mounts I believe at least every 10 years should be replaced "I didn't know this" Replaced mine on a 1987 Legend. First time the crew got on board they asked if I had replaced the engine that it was so much smoother. 2nd I experienced on a about 2007 33' that the owner never pushed the engine past 1800rpm. I believe that would have been the 3 cylinder engine. when we pushed it up around 2600 rpm's after about 5 minutes it smoothed out.
Mine are 24 YO, clean as the day they went in, provide lots of movement, and doing a good job of vibration damping. The initial clearance was 3/8" and they are now down to about 5/16" all around. Take care of them and they'll take care of you.
Get fuel oil on them and they deteriorate quickly.
Correct. The cruising speed is about 80% of RPM max. or 2900 RPM. Due to the obscene cost of motor mounts and the difficulty of swapping them, I would do a HUGE amount of testing before changing them.
OMG, I'm coming to live with you at those prices 
!
Actually, I think we're talking about two different things. Here's the engine mount of a 2GM20F :
It was in a difficult to see location and the rubber on this one was less than perfect due to a very small and hidden fuel leak above it so I replaced it one winter for something to do. A little more pricey (even in CAN $) than yours, even 14 years ago :
And that's 14 years ago. For an engine your size (maybe 4JH ?) I'd guess about $400.00 US ea. at todays prices.
At the labour cost of replacing the mounts, you don't want a cheap knock off either.
Can you post a picture of one of your engine mounts ?
!Actually, I think we're talking about two different things. Here's the engine mount of a 2GM20F :
It was in a difficult to see location and the rubber on this one was less than perfect due to a very small and hidden fuel leak above it so I replaced it one winter for something to do. A little more pricey (even in CAN $) than yours, even 14 years ago :
And that's 14 years ago. For an engine your size (maybe 4JH ?) I'd guess about $400.00 US ea. at todays prices.
At the labour cost of replacing the mounts, you don't want a cheap knock off either.
Can you post a picture of one of your engine mounts ?
Live and learn. You have definitely hit upon a revelation which I had to investigate to believe. And I'm glad I looked.
For a Yanmar 4JH series motor mount :
A single Elebogen #200 mount would be $83.52 USD today. The opposite side of the engine would require a #150 mount at the same price. A Yanmar mount I suspect would be several times this.
The Elebogen appears identical to the Yanmar but are superior in construction. Notice the bonding strap over both rubber blocks.
As opposed to the Yanmar mount with no bonding strap :
I don't know who originally designed this mount but the Elebogen construction appears superior. The lifespan of the elastomer bolcks is still an unknown.
Their website is excellent with everything you would want to know about testing your present motor mounts. Replacement of the mounts is based on the actual testing of the mounts as opposed to any given time period. They also have a section on installing motor mounts both in place as well as with the motor removed. Even if you don't buy their products.
However, the shipping is still a big unknown :
Contacting a major shipping company in Spain may provide a way of shipping to your address at less than highway robbery prices. When I do eventually see poor test results on my mounts, this will be the first place I visit.
For a Yanmar 4JH series motor mount :
A single Elebogen #200 mount would be $83.52 USD today. The opposite side of the engine would require a #150 mount at the same price. A Yanmar mount I suspect would be several times this.
The Elebogen appears identical to the Yanmar but are superior in construction. Notice the bonding strap over both rubber blocks.
As opposed to the Yanmar mount with no bonding strap :
I don't know who originally designed this mount but the Elebogen construction appears superior. The lifespan of the elastomer bolcks is still an unknown.
Their website is excellent with everything you would want to know about testing your present motor mounts. Replacement of the mounts is based on the actual testing of the mounts as opposed to any given time period. They also have a section on installing motor mounts both in place as well as with the motor removed. Even if you don't buy their products.
However, the shipping is still a big unknown :
Contacting a major shipping company in Spain may provide a way of shipping to your address at less than highway robbery prices. When I do eventually see poor test results on my mounts, this will be the first place I visit.
That is more great information for me on the mounts Thank you!
More questions at every step along the way!!
I was finally able to get the shaft out, but not before dropping the rudder. Didn't have nearly enough clearance so I had to dig a hole to get the clearance to drop it, otherwise it was pretty easy. There was some slight play at the bottom bearing of the rudder shaft, not enough to replace the bearing (looks like a really painful process)! Maybe there is a some trick to that??
Also the cutlass is worn as if the shaft was out of alignment. Top of the bearing end on the exit side and bottom of the bearing on the entrance side. (I'll send pics next time) I don't recall if the shaft was angled up or down toward the engine. I have to verify. This caused some slight wear in the shaft which I'm guess is a problem. When I get the new bearing it won't be fully seated at the ends, which probably means a new shaft?? Where can I get one of those off the shelf......Hunterowners.com has the shaft with coupler for $529 ...I don't need the coupling but didn't want to spend that kind of $$ if it isn't going to fix my problem. I have a buddy with a machine shop, he can possibly make me one for less. More to come!
More questions at every step along the way!!
I was finally able to get the shaft out, but not before dropping the rudder. Didn't have nearly enough clearance so I had to dig a hole to get the clearance to drop it, otherwise it was pretty easy. There was some slight play at the bottom bearing of the rudder shaft, not enough to replace the bearing (looks like a really painful process)! Maybe there is a some trick to that??
Also the cutlass is worn as if the shaft was out of alignment. Top of the bearing end on the exit side and bottom of the bearing on the entrance side. (I'll send pics next time) I don't recall if the shaft was angled up or down toward the engine. I have to verify. This caused some slight wear in the shaft which I'm guess is a problem. When I get the new bearing it won't be fully seated at the ends, which probably means a new shaft?? Where can I get one of those off the shelf......Hunterowners.com has the shaft with coupler for $529 ...I don't need the coupling but didn't want to spend that kind of $$ if it isn't going to fix my problem. I have a buddy with a machine shop, he can possibly make me one for less. More to come!
Here's where I got mine. Price varies with material chosen. Don't forget to have the new coupling fit and faced to the shaft.
www.deepblueyachtsupply.com
Stainless Steel Inboard Propeller Shafts | Deep Blue Yacht Supply
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