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Discussion Starter · #1 ·
1983 Cal 3-27. Yanmar 1GM.

I've had this problem intermittently for a while, but it has suddenly gotten quite bad. Early on, on rare occations, a terrible squeel could be heard shortly after putting the transmission in gear. On those occations it could be stopped by throttling up.

Now, it happens every time the transmission is in gear and it can't be stopped.

Thinking it was the stuffing box I loosened it up to the point that it drips even if the prop isn't spinning but that hasn't helped.

My next step is going to be to replace the packing gland.

Do you have any other ideas as to cause and solution?

Thanks,

Matt
 

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Have you checked the oil level and condition in your transmission? Does the oil smell burnt?
 

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Slipping clutch?

Cable adjustment?

Are you sure it is in the transmission? Have you eliminated the alternator/alternator belt as a potential cause?
 

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Discussion Starter · #4 ·
I've just checked my maintenance records and it's been an embarassingly long time since I've changed the transmission oil or packing gland. I'll do both today and report back.

I'm pretty sure that it has to do with the prop shaft spinning - transminssion, packing gland, something else. It doesn't happen at all out of gear, no matter the rpm.
 

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I'd say that you need to narrow it down to either transmission or shaft or something else. I'd start by uncoupling the transmission from the shaft.

As James mentioned it could also be an accessory belt, common cause of squeals.

The fact that it used to stop when you throttle up suggests the tranny but you really need to confirm before you can go farther into the diagnosis.

FWIW I had the same symptom, squealing that would stop when throttled up. In my case it turned out to be slipping clutch.
 

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Discussion Starter · #7 ·
Good ideas. Thank you.

I went under the boat and found the prop difficult to turn by hand.

I opened the stuffing box and found less water than I expected coming in, but my expectations lack experience, so I don't know if I'm right or not. Witness the water ingres for yourselves:


I unbolted the prop shaft from the transmission, but the shaft and transmission still turned together. So, I went back under the boat and twisted the shaft while pulling out and created some separation. I still found the prop difficult to turn. With the shaft and transmission completely separate and engine on and in gear it sounds lovely. I surmise a shaft problem.

What wisdom does the collective have to offer?
 

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Ok good. so I think you can rule out the transmission and accessories.

Sounds are hard to explain on a forum (one mans squeal is another mans squeak) but at this point the source of the noise is either
- stuffing box (although I've never heard a stuffing box squeal)
- cutlass bearing
- anything else?

Have you considered removing the old packing and re-packing the stuffing box? Its an easy and inexpensive experiment. Keep in mind it's a dicey proposition to do it with the boat in the water, but it can be done. If you do, I'd wrap the shaft (with a rag or something) from the outside and make sure the bilge pumps are working before starting.

I'd say that The amount of water you have coming in with the stuffing box nut loose is normal. Expect a lot more to come in if you remove the packing.

And in regards to the friction that you feel when spinning the prop (again that's hard to describe on a forum), that might suggest the cutlass bearing as the culprit.

Btw can you post a video that includes the sound of the squeal?
 

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Discussion Starter · #9 ·
It's a squeal. Long, never ending, blood curdling squeal. A holy-crap something-is-bad-wrong-make-it-stop-now squeal.

I can't provide a video with the audio of the squeal for a while. It's going to take me a little while to bolt the shaft back to the transmission, and my weekend is over.

However, I did put the transmission in gear with engine running and no packing at all in the stuffing box and it still made the noise. Ergo, it's not the stuffing box.

Looking at the video I posted, if you move aft (which I have no video of) there's what looks to me like radiator hose. It's got double hose clamps at each end. What's in there?
 

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That's the stuffing box hose, there is nothing in there except sea water. it's the hose that seals the stuffing box to the shaft log.

You've done all the right things here and it sure sounds like you've narrowed it down to the cutlass bearing.
 

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Discussion Starter · #11 ·
Which is the one damn thing I can't do in the water.

Well, it can sit quietly until I can get up there and make another recording.

What, exactly, is a shaft log?

What other symptoms might I notice with a bad cutlass bearing? I expected some wiggle, but I find none.

And I know this is a question that can't be answered, but how long does a cutlass bearing last? The one on it now has been there for seven years. I motor about 45 minutes a week, give or take.
 

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Discussion Starter · #12 ·
Another question about this . . . could there be something in tube in the hull that the prop shaft passes through? Is there a bushing or something in there? Could something have gotten in there causing it to bind?
 

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Discussion Starter · #13 ·
I'm still thinking about this. Please forgive my frequent posts . . .

It seems to me that if the cutlass bearing were worn, and the shaft was disconnected from the transmission, that the prop would be *easier* to turn than normal, not harder. Yes?

Also, another data element that I had forgotten for a while - while the other-worldly squealing is going on the transmission is very difficult to shift in and out of gear.

Does any of this lead toward likely problems?
 

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its always difficult to diagnose without being there. So these are just some of my thoughts, opinions and conjecture:

Some possible causes of a squeal:
- accessory belts: eliminated
- transmission cones or clutch: eliminated
- stuffing box - eliminated
- Cutlass bearing
- some odd harmonic in the drive line or prop (might be described as "singing" rather than "squealing" and it would change with RPM)

current symptoms include:
- constant squeal when the shaft turns
- squeals at all RPMs
- shaft is hard to turn by hand
- there is no play side to side in the shaft

Additionally: "while the other-worldly squealing is going on the transmission is very difficult to shift in and out of gear."
- This seems to implicate the transmission again. Perhaps you can't eliminate it just yet?
- Is the transmission easy to shift with the shaft was disconnected?

> could there be something in tube in the hull that the prop shaft
> passes through? Is there a bushing or something in there?

well it depends on your boat. On mine the cutlass bearing is at the aft end of the shaft log. if you have a prop strut I believe you'd have the cutlass bearing in the strut and a bushing or seal of some sort at the aft end of the shaft log.

> What other symptoms might I notice with a bad cutlass
> bearing? I expected some wiggle, but I find none.

Agree you usually expect play in a failing cutlass bearing. But a bearing can have a number of failure modes. Its not unheard of for a bearing to fail, or be on its way to failure, without noticeable play.

A few more thoughts:
- when you separated the shaft from the transmission did you check that you had good alignment?
- are the motor mounts in decent shape?
- when you slid the shaft out a bit did you inspect the newly revealed portion of the shaft for wear, scoring, corrosion?
 

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Discussion Starter · #15 ·
I do have a strut between where the prop shaft exits the hull and rudder. This is where the cutlass bearing is.

The transmission is easy to shift when the prop shaft is disconnected.

I have another theory now, but it's based on complete ignorance of the transmission. Is it possible that something is binding the prop shaft (it is difficult to turn) and that binding it putting extra load on the transmission? Could that extra load be enough to make the clutch squeal?
 

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again just conjecture:

- binding shaft causing the clutch/cones to slip/squeal - yes this is possible if the clutch is very worn and/or the shaft very hard to turn. it fits with your symptoms too, including that it has gotten worse over time.
- misaligned shaft putting a lot of longitudinal stress on the trans and driveline when bolted up.

to check your theory: Use an optical tachomer (they are inexpensive) to check that the output shaft rpm at a given engine rpm (use the optical to measure both, dont go by the engine tach). check the shaft RPM with the prop shaft bolted up and free. if they are different it would indicate slippage and would confirm your theory.

here is the tach that I have:

also check anything that is putting sideways stress on the shaft, in particular shaft alignment (check that at the coupler) and motor mounts (if broken alignment will change with load ... check them with a big crowbar).

also might check the transmission output shaft bearing for play or roughness. unbolt the shaft, wiggle and turn it
 

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squeels are from the tranny...bet you a buck...

if it were cutlass bearing youd be hearing tapping knocking sounds...

and not squeeling...

clutch plate, cones, etc...culprit

good luck
 

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Discussion Starter · #18 ·
Good ideas, Bristol. Thank you.

I've never been quite clear on how to check the shaft alignment. Can you point me to a good write up on that?

And, what do you mean by checking the motor mounts with a crowbar?

Finally, a confirmation check. I should unbolt the prop shaft, turn the engine one, put transmission in gear. Then check the engine RPM with the digitial tack and write that down (let's call it 1000 for this discussion). Then, check the rpm of the hub at the back of the transmission and write that down.

Then, I'm going to bolt the prop shaft up, turn the engine on, put transmission in gear, and get engine back to 1000 rpm, and check the rpm of the prop shaft. Yes?
 

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By any chance, did you have dock line get wrapped up in the prop? Could be a bent shaft.

Regards,
Brad
 

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Christian is right, that sound is typically from the trans cones or clutch (btw which transmission is this?).

And Brad is right on .... you should definitely check for a bent shaft.

> I've never been quite clear on how to check the shaft alignment.
> Can you point me to a good write up on that?

Here is one: http://www.sailnet.com/forums/1015260-post2.html
but I'm sure you can find a better write up online somewhere. To Brad's point, when you turn the prop shaft by hand, with the flanges close, if the shaft is bent you will see the prop side flange wobble relative to the engine side flange.

>what do you mean by checking the motor mounts with a crowbar?

jam the crowbar in there and pry on mount to see if there is play. Its rubber and it will deflect a bit but there should not be any play. If there is, the failure mode and extent of it will be obvious (sheared bolt, torn rubber, etc)

> Finally, a confirmation check ...

yes that is correct. the idea is to determine if there is slipping when you hear the squeal. you'll want to choose an RPM that you know will cause the squealing.

Oh and how about the transmission fluid? does it look or smell burnt? it would be a good time to change it.
 
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