Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 29-07-2014, 20:50   #1
Registered User

Join Date: Jun 2011
Location: Victoria, Canada
Boat: 2009 Beneteau 40
Posts: 10
Yanmar Engine, Prop Shaft Vibration

Hi Folks
Have Beneteau 40 with yanmar 4JH4AE engine, KM35P cone clutch transmission.
Had transmission problem. The cone clutch was lapped and trans put back in. But I now get a vibration set in at 1200 rpm which goes away at 1600 rpm.
Would love to have some ideas before mechanic comes to look at things in two days time.
Could alignment problem come and go over this sort of range or could there be other causes.
thanks, JohnB40
__________________

__________________
JohnB40 is offline   Reply With Quote
Old 29-07-2014, 22:59   #2
Moderator Emeritus
 
Ex-Calif's Avatar

Cruisers Forum Supporter

Join Date: May 2007
Location: Singapore
Boat: Maxi 77 - Relax Lah!
Posts: 11,514
Images: 4
Re: Yanmar engine,prop shaft vibration

There could be many causes.

It could be imbalance, alignment or engine/trans mount related. It could (conceivably) also be related to engine components depending on the frequency.

With proper diagnostics equipment frequency and amplitude can be isolated and suspect components targeted. But I suspect you mechanic is going to be doing some guessing as it is unlikely he has the proper equipment.
__________________

__________________
Relax Lah! is For Sale <--- Click
Click--> Custom CF Google Search or CF Rules
You're gonna need a bigger boat... - Martin Brody
Ex-Calif is offline   Reply With Quote
Old 30-07-2014, 01:36   #3
Registered User

Join Date: May 2010
Posts: 666
Re: Yanmar engine,prop shaft vibration

Let's assume that the clutch was overhauled correctly. Perhaps the problem with the clutch might have been caused by the system after it namely:
bent drive shaft
drive shaft not reinstalled in alignment(maybe there might have been a shim in there)
worn cutless bearing (that's what caused my vibration)
bent propeller blade
poorly aligned propeller
worn or poorly installed stuffing box

All of these can cause vibration and some will resonate at particular frequencies.

try these before you get an expert:

pull on the shaft side to side and see if there is wear in the cutless bearing
undo the bolts holding the shaft to the gearbox (warning, the shaft might slide out) now rotate the shaft and see if there are any tight spots as it turns (maybe a bent shaft)
reinstall shaft, rotate it and measure from a fixed point on the hull to a similar point on each propeller blade. Check distance and angle. This MIGHT show a bent blade.

It will be complicated to do any work while the boat is in the water. You might consider a total rear end replacement. but remember that all of this assumes that the clutch overhaul was done correctly.
__________________
dlymn is offline   Reply With Quote
Old 30-07-2014, 12:08   #4
Registered User

Join Date: Jun 2011
Location: Victoria, Canada
Boat: 2009 Beneteau 40
Posts: 10
Re: Yanmar engine,prop shaft vibration

Hi again folks

Getting some very useful commment. Thanks.

Should have also said the vibration does not occur with engine in neutral.
I've no idea if the couplings on transmission and prop shaft were reconnected with the same holes matched up .... would that be a possible thing worth trying? That is, rotate shaft 45 degrees and rebolt. Do again etc and see if one position is good .... as you see I'm no expert!

thanks, JohnB40
__________________
JohnB40 is offline   Reply With Quote
Old 30-07-2014, 12:34   #5
Registered User

Join Date: Aug 2009
Location: Port Welshpool Australia
Boat: sold swan new cat under construction / Canados 50s
Posts: 755
Images: 16
Send a message via Skype™ to beneteau-500
Re: Yanmar engine,prop shaft vibration

For my two penny's worth A/ check the prop shaft at 1200 rpm ie it's position then rev up to 1900 rpm (ie in gear) see if shaft floats forwards to wards engine B/ do you have a Aqua drive coupling between g/box prop shaft C/ I have had this before lost one half of my anode on prop shaft the remaining half was seized on shaft it took me a full day to realise what was casing the dam vibration
__________________
beneteau-500 is offline   Reply With Quote
Old 30-07-2014, 13:46   #6
Registered User

Join Date: Jun 2011
Location: Victoria, Canada
Boat: 2009 Beneteau 40
Posts: 10
Re: Yanmar engine,prop shaft vibration

Hi
No Aqua drive coupling.
Zinc comment interesting but timing seems quite likely that taking trans out for repair had something to do with this.

JohnB40
__________________
JohnB40 is offline   Reply With Quote
Old 30-07-2014, 13:51   #7
Registered User

Join Date: Aug 2009
Location: Port Welshpool Australia
Boat: sold swan new cat under construction / Canados 50s
Posts: 755
Images: 16
Send a message via Skype™ to beneteau-500
Re: Yanmar engine,prop shaft vibration

Whilst I am not familiar with your g/box just wondering if damper plate if you have one between g/box and engine is lined up properly as we'll just a thought
__________________
beneteau-500 is offline   Reply With Quote
Old 30-07-2014, 13:56   #8
Guy
Registered User

Join Date: Feb 2013
Location: So. Oregon, USA
Boat: Seafarer36c
Posts: 4,308
Re: Yanmar engine,prop shaft vibration

Quote:
Originally Posted by JohnB40 View Post
Hi again folks

Getting some very useful commment. Thanks.

Should have also said the vibration does not occur with engine in neutral.
I've no idea if the couplings on transmission and prop shaft were reconnected with the same holes matched up .... would that be a possible thing worth trying? That is, rotate shaft 45 degrees and rebolt. Do again etc and see if one position is good .... as you see I'm no expert!

thanks, JohnB40
I would go 90deg or 45 but a major change. I could be nothing more than the prop, shaft and coupling combo slightly out of balance.
__________________
Guy is offline   Reply With Quote
Old 03-08-2014, 09:40   #9
Registered User

Join Date: Jun 2011
Location: Victoria, Canada
Boat: 2009 Beneteau 40
Posts: 10
Re: Yanmar engine,prop shaft vibration

Thanks folks. I feel much better informed ... never a bad thing. It does seem to have been just the alignment issue. Vibration seems to have been fixed.
Still concerned why Yanmar cone clutch would crap out after such a short period of use ... the KM35P trans seems to have a load of problems from searching the web. It was run as per Yanmar instuctions ... allow to spin while sailing. Ensure clutch cable adjusted. Change oil etc
JohnB40
__________________

__________________
JohnB40 is offline   Reply With Quote
Reply

Tags
engine, yanmar

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Prop shaft vibration jtinterland Propellers & Drive Systems 15 09-12-2015 00:14
Engine mounts; engine vibration on gear ErikFinn Engines and Propulsion Systems 18 07-03-2013 22:58
2YM15 Installed - Transmission "Whine" and Shaft Vibration ? fishfinder Engines and Propulsion Systems 5 04-12-2012 20:27
serious prop shaft vibration drinky Propellers & Drive Systems 26 27-01-2009 05:54
Vibration fwd gear problem 2 blade gori prop 737flyboy Engines and Propulsion Systems 5 11-01-2006 17:28



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 16:20.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.