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Vibration

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Created by Shotchas > 9 months ago, 2 May 2014
Shotchas
NSW, 87 posts
2 May 2014 11:15AM
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While checking out the engine running on Maggie IV, I found it ran very smoothly in neutral, (on a hardstand). When I engaged forward and reverse, there was a fair amount of vibration and roughness as the shaft and prop spun. It has a two blade prop.
Is this normal when there is no load on the prop? The prop turns freely by hand when in neutral with no obvious free play in the bearing. The engine, gearbox, shaft and bearings have 41 hours on them although it has been sitting for six years on a hardstand.
Any ideas?

Shotchas
NSW, 87 posts
2 May 2014 4:23PM
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On closer inspection, I put more pressure on the prop and found there is close to 2mm play at the cutlass bearing, so it looks like that was not replaced when the engine was.
This is the stern gland set up.



If the cutlass bearing needs replaced, is it a matter of loosening the grub screw at the gearbox and pulling the shaft from the outside? Do I have to loosen something in the stern gland? Lock nuts under the hose?
This is my first boat with a diesel so it's a learning curve. The black hose is for grease with a nipple on the end for easy access.


HG02
VIC, 5814 posts
2 May 2014 6:26PM
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First of all spray some CRC on the grub screw it might help later and give those bolts spray also . Then when and if you remove the prop shaft it might help to undo the grub screw.
There would be more capable sailors on here to give you advice on your cutlass bearing . Grease the the nipple after use thats what I do. and buy some Bilger cleaner

Ramona
NSW, 7653 posts
2 May 2014 6:31PM
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Are you saying there is 2mm gap between the shaft and the cutlass bearing or you can move the shaft that much?

To pull that shaft out to replace the stern bearing you will have to unbolt the flange. Take out that bolt that's visible in the flange. Loosen off the stern gland if its adjustable. You may have to pull the propeller too depending on what sort of yacht this is. The shaft is usually on a taper with either a keyway or that bolt through the flange. Do not use a hammer anywhere this unit at anytime! A selection of various length bolts and sockets will get the taper out of the flange.

You don't have a shaft anode that's loose by any chance!

Shotchas
NSW, 87 posts
2 May 2014 6:34PM
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.be

This is a short video of the play at the prop.
HGO2. When I get a new bilge pump in there I'll certainly give it a good clean out. I had thought about using detergent and hot water but I'll check out Bilger Cleaner.
Cheers

Ramona
NSW, 7653 posts
2 May 2014 6:34PM
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After a quick re read I realized you ran this on the hard stand!!!!!!!!!!!!

The rear bearing will almost certainly be water lubricated. It will swell slightly after being in the water.

Shotchas
NSW, 87 posts
2 May 2014 6:40PM
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Ramona, It's a Clansman, and yes the shaft anode was loose on the bolt where it attaches to the hull.

nswsailor
NSW, 1441 posts
2 May 2014 6:47PM
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I had to replace my cutlass bearing last year as it was just making too much noise and producing too much vibration.
Turns out I had about the same play as yours Shotchas.

Had it done at Marong Pt Marina, it was just not a case of getting the cutlass bearing in in any old way ...
they in fact put it on a lath and spun it down to the correct diameter.

It was then glued in place with industrial Loctite E.pox e glue.

The motor was then realigned...

What a difference that all made.

Won't tell you what it cost, but they saw me coming!

Ramona
NSW, 7653 posts
2 May 2014 6:51PM
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That's too much movement.

Isn't technology wonderful! Short video is worth thousands of pictures. I'm a big fan of instructional videos on Youtube.

Shotchas
NSW, 87 posts
2 May 2014 6:57PM
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Just to clarify, I only got the boat last week and it has been out of the water for six years.
I like trying the easy options first, so I'll see if I can get the bearing wet for a while then try again for a few seconds.
I didn't run it for long when it vibrated, so hopefully no damage was done running it dry.

Ramona
NSW, 7653 posts
2 May 2014 8:08PM
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Really it needs to be in the water several hours to swell and the boat to resume the correct alignment. I think you should plan on fitting a new rear bearing now while its out. Not expensive and not hard to do especially as your on the hard standing already. The Clansman would probably have a stock size bearing.

MorningBird
NSW, 2679 posts
2 May 2014 9:10PM
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I had major engine vibration when I engaged forward gear after all my shaft work. It turned out the gear drive cable was seized and the gearbox wasn't engaging gear. As the boat has been unused for 6 years disconnect your cables and make sure they move freely.

HG02
VIC, 5814 posts
2 May 2014 9:44PM
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Select to expand quote
MorningBird said..

I had major engine vibration when I engaged forward gear after all my shaft work. It turned out the gear drive cable was seized and the gearbox wasn't engaging gear. As the boat has been unused for 6 years disconnect your cables and make sure they move freely.


and clean and grease your cables make so much difference Id change that cutlass while its home go through the whole boat while is on the hard
Snotchas now is your chance. Id try any degrease for the bilge scrub her out then she will smell nice later on

Lexmark
VIC, 218 posts
2 May 2014 9:50PM
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HI
Yes I fully agree While on hard stand go all over her, but dont plan on having any more spare time, and keep the cheque book handy, but it is all good fun :)



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"Vibration" started by Shotchas