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  #1   IP: 199.36.132.194
Old 11-28-2018, 05:49 PM
LordGothington LordGothington is offline
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Drive train noise, stuffing box leak, etc

Ahoy!

When motoring, I feel that the noise coming from the propeller area is a bit excessive -- sounds like I am on a B-52 bomber. But this boat is new to me, so I don't know what 'normal' sounds like.

Recently I have been doing a lot more motoring (650+ miles, and 600+ more to go). I have had to tighten the stuff box several times -- and it seems to be needing attention more frequently. I am on a Tartan 27 Yawl.

Additionally, I noticed that when in gear at idle speed I can see a noticeable wobble of the stuffing box.

I have no real idea if the noise and vibration are normal or not as I have only be on one other similar boat and it had a 3-blade prop.

Right now the boat is in the water -- I am at a facility that can haul it out if/when needed.

Since it is in the water it seems like a good place to start is to check the alignment. On this boat, the engine is a hard mount -- there is no rubber or other vibration reduction stuff. I found that all the mount bolts where a bit loose -- which is not a great sign.

The next step, I believe, is to loosen the 3 bolts that attach the shaft coupler to the transmission. I think I remove 2 and leave one loosely attached and use a feeler gauge to check the alignment.

If everything seems ok, then the next step would be to haul the boat out of the water.

Once the boat is out of the water I can try wiggling the prop around and see if there is too much slop in the cutlass bearing. Next I can remove the propeller and see if the wobble goes away. (Making sure to provide water for the cooling system) If the wobble goes away then the problem was probably an unbalanced propeller. If the wobble remains, it is more likely a bent shaft.

The next step is to remove the shaft (and order a new coupling -- perhaps the split one), and check if the shaft is straight.

So... I am currently stuck on the step where I loosen the 3 bolts holding the coupler to the transmission. With the boat in the water it is pretty hard to stop the shaft from rotating when I try to loosen the bolts. It is tempting to use a pipe wrench on the shaft -- but I've heard that is bad for the shaft. If I was certain to need a new shaft then it wouldn't matter, but I have not reached that point yet.

I've heard it said that an 18" pipe wrench can be used to grab onto the coupler -- but I would assume that would not be good for the coupler. I think in the situation I was reading about they were attempting to replace the coupler on the engine side and just needed to hold it still to remove the nut.

So far I have been soaking the bolts in penetrating oil. I am a bit fearful of using a torch to apply heat right underneath the gas tank. But I do have a small butane torch I could try.

If the boat was out of the water, I could use a 2x4 to stop the propeller from spinning.

So.. another option is to wait -- but I am not sure how bad of an idea that is. I am currently at Green Turtle Bay in Grand Rivers, KY. It's cold here and only getting colder. But I am headed to Mobile, AL where I was planning to have the boat hauled out. So I'd love to just wait until I get there.

But, I've read that the vibrations could cause damage to the transmission. Is 600 miles way too long to wait? Or not far enough to be a big difference.

In this boat there is very little propeller shaft sticking out and the only support is the stuffing box/cutlass bearing/etc that goes through the hull.

I have some other inconclusive data.

If I try to wiggle the shaft from inside the boat near the stuffing box, I can't really feel any play.

If I turn the propeller shaft by hand I am not able to see any wobble. I also tried putting a stick across the nut to amplify the movement and show it like an indicating needle across the hull. I still was not able to see any movement when turning the shaft by hand.

I do see the wobble in both forward and reverse.

I am sure that the tip of one of the blades is slightly bent -- not sure how much bend would be needed to cause issues. (I also don't know how it happened -- was like that when I bought it).

I have no idea when the stuff box was last repacked or when the cutlass bearing was last replaced. I know the engine was rebuilt a decade ago -- so perhaps then.

In summary:

1) can this wait another 600 miles

2) how can I get those bolts loose when I am in the water.

Thanks.
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  #2   IP: 72.194.222.152
Old 11-28-2018, 08:10 PM
JOHN COOKSON JOHN COOKSON is offline
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I don't know the answer to your question but I do have one of my own.
What is the dip rate out of the stuffing box when the engine is in gear?
If you get the packing to tight you can burn the shaft. Not good. Hope you haven't overtightened the stuffing.
IMO a bent prop would cause the the vibration. Any chance that there is something wrapped around the prop that is making the vibration worse?

TRUE GRIT

Edit: One time I had a racket that I was sure was related to the drive train. It turned out to be the alternator. I diagnosed it by removing the belt and starting the engine.

Last edited by JOHN COOKSON; 11-28-2018 at 08:15 PM.
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  #3   IP: 199.36.132.194
Old 11-28-2018, 08:22 PM
LordGothington LordGothington is offline
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I have been pretty conservative when tightening.

I'll tighten it so that it only drips every minute or so when the shaft is not turning. Then motor for 10-12 hours and it will be dripping once a second when the shaft is not turning.

I am not sure how much is is dripping underway immediately after I tighten it -- because I am trying to dodge towboats and not run aground. Solo cruising on rivers makes it tough to spend a lot of time with my head in the engine compartment.

There is always a chance something is fowled on the prop -- but the noise has been there since I put it in the water. That said, I launched it in the Chicago river, so maybe it got immediately fowled.

I guess I should also add that I have been running down silty rivers like the Mississippi -- but none of the locals think the mud could be causing the stuffing to wear out faster.

Last edited by LordGothington; 11-28-2018 at 08:26 PM.
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  #4   IP: 131.162.198.114
Old 11-28-2018, 08:36 PM
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Peter Peter is offline
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Dear Lord,

I had some shaft wobble issues this spring after pulling the engine to replace the rear seal and thrust bearing. My repair was motivated by an oil leak but I decided to replace the thrust bearing while I was there and the subsequent reduction in noise was dramatic!!! It should not sound like a B-52.

The shaft should not wobble. This will put stress on the stuffing box and the thrust bearing.

How to loosen the nuts in the water - I had success using one of those rubber strapped oil filter wrenches around the coupling. However, my bolts had been removed very recently so maybe I had it easy.

You are on the right track re aligning. I read somewhere that one should try to get the height about right with the rear mounts and fine tune the alignment with the front mounts. This strategy worked for me.

Can it wait ? If it was my boat I would fix it. I think you risk further damage to the thrust bearing - perhaps catastrophic.

Peter
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Old 11-28-2018, 09:04 PM
LordGothington LordGothington is offline
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I'm looking at some pictures of adjustable rubber strap wrenches online and those looks very promising. I'll have to grab the courtesy car tomorrow and make a run to the hardware store.

My inclination is to not go anywhere until I have this issue resolved. I *think* I have made it far enough south that I will be able to get fuel and stuff even if I am delayed a bit longer. Though non-winterized pumpout stations are pretty rare these days. This place has a full service center and the pool and sauna are still open, the wifi is reliable, etc. So I'd rather be stuck here than some place where nobody can help me.

It's my understanding that the Atomic 4 uses SAE (imperial) wrenches, but it seems to me that the 14mm fits nuts a lot snugger than the 9/16. I'm tempted to pick up a longer 14mm wrench (for more leverage) unless there is some reason why using the 14mm would be more likely to strip the nut.
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  #6   IP: 24.152.132.140
Old 11-29-2018, 08:26 AM
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ndutton ndutton is offline
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Continued tightening of worn packing only serves to add drag to the shaft, does not manage drip for very long and at some point damages the shaft surface which will affect the replacement packing's ability to seal properly. You may even impart enough drag to stall the engine at low RPM. Since this boat is new to you it's doubtful you know the age of the current packing so based on your first post and the benefit of "making the boat yours" I suggest the time has come for replacement. You'll be amazed at how little pressure it takes for fresh packing to seal properly.
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  #7   IP: 32.211.28.40
Old 11-29-2018, 09:51 AM
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Al Schober Al Schober is offline
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LG,
Backing off the coupling and checking the gap between the flanges will give you a good start. I recommend you put alignment marks on both flanges, then remove all the bolts. The shaft side of the coupling won't drop into the bilge as it has a pilot that fits into the engine side of the coupling.
Check the initial alignment - biggest gap & where? Then rotate the engine 180 degrees. Gap and location shouldn't change if the engine flange is running square. Do it again, but rotating the shaft and it's flange 180 degrees. Again, it shouldn't change if the shaft is straight and it's coupling is square.
If the propeller shaft isn't running true, doing an engine re-alignment is a waste of time and could actually make things worse!
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