Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Sign in to follow this  
Levi900RR

Vibration...

Recommended Posts

Levi900RR

Last year towards the end of the season I dung my prop slightly. I was idling through a sandbar and must have just grazed the sandy bottom and hit a clam or little rock or something. I could see a very slight ding in the prop which caused a slight vibration. I ran it the rest of the year like this. Maybe 10 hours.

Fast forward to this year. I get the boat out, and as you can see in my tune up thread the ignition system was a mess. The engine running rough REALLY exaggerated the vibration. SO... I did the tune up and bought a 1235. Thinking I'd just true up my 381 and keep it as a spare. Well, there is still a slight vibration in the drive line. I did some research and did a visual inspection last night. The shaft doesn't have any marks on it, the coupler looks good (I found one thread where one guy had some loose / missing bolts in the coupler) I turned the prop by hand and couldn't see anything visibly wrong with the prop or shaft. I haven't done the wire trick yet to see if there is a minor bend in the shaft.

Is there anything else I should be looking at here? Starting to scratch my head. Also, I brought my feeler gauges down to check the alignment but I assumed you checked it at the coupler. Mine doesn't have any gap at all. Tried to snap a few pics.

Thoughts?

3B0B2B57-0420-4CBF-9D13-02920C5BA4C8.jpg

6CD07F4A-29EF-42C5-AB0A-A8AB2541A660.jpg

9249372D-0D72-4B94-A3A0-01A8A6092E64.jpg

Share this post


Link to post
Levi900RR

Just did some more reading... apparently I have to unbolt the coupler in order to check alignment :Doh:

EDIT: looks like I should check my motor mounts as well.

Edited by Levi900RR

Share this post


Link to post
DIE2SURF

Yup, unbolt. I just did mine a few weeks ago. Not terribly hard to adjust engine side/side. As for up/down, not sure.

In case you haven't seen this, it's a good tutorial as well: https://www.youtube.com/watch?v=3_w0LvD6gEc

Share this post


Link to post
Levi900RR

Was yours off? Were you able to eliminate any vibration?

Share this post


Link to post
DIE2SURF

Yes, mine was .006. A very slight, long feeling whup-whup-whup only at 5 mph. Got it aligned to .002. I believe under .003 is good enough for Govt., but I don't remember for sure, check your specs and the video mentions what's acceptable tolerances.

When the engine finally moves side/side (pry-bar), really makes a jolt. It's a bit of a sudden shock; interesting to say the least. Getting it properly aligned within spec eliminated all vibration, smooth a silk after that.

I stated something incorrectly earlier: You don't have to unbolt the coupling all the way, just loosen so you can get feeler gauge in.

Edited by DIE2SURF

Share this post


Link to post
Levi900RR

Thanks for the tips. I'm struggling to understand how it got out of alignment to start with....

Share this post


Link to post
oceanbu

Levi, I would be interested to know how you make out with this if you choose to do it yourself. I imagine there are lots of boats out there that are ever so slightly out.

I would think this is like a reel lawnmower where as soon as you hit something even a little twig or rock on your lawn the alignment is out.

Share this post


Link to post
Levi900RR

Man... I wacked my trailer with my Skier once, WAY harder than this little scuff in the sand, like a big banging noise etc... I had the prop rebalanced and it was smooth as silk. I barely scraped a sandy bottom and didn't hear / feel any significant impact.

Weird.

Another question. Will I do any damage running it this way? Or is it just an annoyance? If I could put it off until its not 90 and sunny I'd love to.

Share this post


Link to post
AndrewSchear

Bergeron Engineering (local in phoenix,az who machines new replacement shafts) told me that while most people shoot for .005", the reality is that .030" or about what a human eye can see is close enough to not cause any binding or harmonics. Mine had about .015" total variance when I got it installed and it runs smooth.

Share this post


Link to post
Levi900RR

So what do you think about finishing up the season with a little vibration?

Share this post


Link to post
Levi900RR

:bump: Sorry to beg... Anyone have thoughts on running like this? I really want to use the boat this weekend but don't want to cause any permanent damage.

Share this post


Link to post
Bozboat

:bump: Sorry to beg... Anyone have thoughts on running like this? I really want to use the boat this weekend but don't want to cause any permanent damage.

I would run it the rest of the season, stopping only to fix the major problems, (ones that leave you DRT) then spend the off season fixing everything, that seems to work for me.

Edited by Bozboat

Share this post


Link to post
DIE2SURF

How bad is the vibration? What speed(s) is it most noticeable? Does it ever disappear at higher speeds? These are all factors for me when I make such decisions. I ran mine for a season with it .006/7, with just a slight vibration at 5mph, but it completely disappeared at 10+mph.

If you have a vibration at higher speeds (20+), I would think it would be a bit more concerning, but I'm no expert.

Share this post


Link to post
Levi900RR

It is only noticeable below 10MPH. Totally goes away after that, AND it's not really bad. Only me and some of my buddies who own boats notice it.

Share this post


Link to post
UWSkier

Last year towards the end of the season I dung my prop slightly. I was idling through a sandbar and must have just grazed the sandy bottom and hit a clam or little rock or something. I could see a very slight ding in the prop which caused a slight vibration. I ran it the rest of the year like this. Maybe 10 hours.

Fast forward to this year. I get the boat out, and as you can see in my tune up thread the ignition system was a mess. The engine running rough REALLY exaggerated the vibration. SO... I did the tune up and bought a 1235. Thinking I'd just true up my 381 and keep it as a spare. Well, there is still a slight vibration in the drive line. I did some research and did a visual inspection last night. The shaft doesn't have any marks on it, the coupler looks good (I found one thread where one guy had some loose / missing bolts in the coupler) I turned the prop by hand and couldn't see anything visibly wrong with the prop or shaft. I haven't done the wire trick yet to see if there is a minor bend in the shaft.

Is there anything else I should be looking at here? Starting to scratch my head. Also, I brought my feeler gauges down to check the alignment but I assumed you checked it at the coupler. Mine doesn't have any gap at all. Tried to snap a few pics.

Thoughts?

3B0B2B57-0420-4CBF-9D13-02920C5BA4C8.jpg

6CD07F4A-29EF-42C5-AB0A-A8AB2541A660.jpg

9249372D-0D72-4B94-A3A0-01A8A6092E64.jpg

I don't really have an answer for you but I do like your use of the word dung as past tense of ding. :)

Share this post


Link to post
DIE2SURF

Sounds exactly like mine did. I ran it fine. I was the only one who could really notice it, and would ask other s if they noticed it (which they never did until I pointed it out).

I would run it.

My issue began after I hit something pretty hard with the prop. I got the prop fixed, but could still tell a slight warp-feel in the drive at slow speed. The shaft was fine. That's when I went to the coupler, and found the issue. I was almost thinking that when I banged the prop, maybe it was enough of a jolt to move the engine out of place just slightly.

When I realigned the engine, it took only 1/4" shift starboard to get the coupler true to spec.

Edited by DIE2SURF

Share this post


Link to post
Levi900RR

Thanks for the feedback I'm going to run it and fix it this fall on the trailer. Much easier than lugging all my tools down to the dock.

Share this post


Link to post
8senuf Gang

Great thread. My 01 23LSV has had a slight knock in driveline at low speed for years. Yesterday after a short run, put her in gear and "clunk, clunk, clunk"! Forward and reverse. Slight leak at stuffing box but quick inspection showed nothing. Putting her on the trailer this morning. We'll see.

Share this post


Link to post
Levi900RR

So I got fired up to do some mid season maintenance on the BU. I made a quick call to the local dealer and they say they can do a motor / shaft alignment next week and have the boat back to me in a day. Think I should wait it out and try to DIY it this fall or just have them do it? I was taking a look at the motor mounts this morning and I couldn't really get my mind wrapped around how it would all work. I'm sure if I had a whole day and some help from a friend I could figure it out but I'm starting to think maybe outsourcing this project might be good.

Thoughts? Anyone actually do this themselves? How long did it take and how hard was it? Man, I have a free 90 mins right now. Maybe I should just go unbolt the coupler and see what happens :lol:

Share this post


Link to post
DIE2SURF

Post #3, 5. I recommend watching the video. Took me 1 hour.

I would absolutely check the coupler with feeler gauge. That will tell you if you actually have an alignment issue to bother taking into the shop, and possibly what/where the issue is. You can always just tighten the coupler back up if you decide not to tackle aligning yourself.

Loosen coupling bolts enough to get feeler gauge(s) in. Determine where the alignment is off (side-to-side or top-to-bottom). If side to side, loosen front motor mounts where they connect to trunnions. I used a pry bar to pry against the mount, and against a block of wood at the stringer. Applying plenty of pressure on the pry bar to the mount; tap opposing mount with a large ball peen hammer or stubby sledge. The blow will allow the engine enough shock to break free from it's weight on the trunnions and will jolt over. (2 people are definitely better than 1 in this scenario.)

If you can get the front of the engine to move in the direction on the large gap, then the gap should close on the wide side, and possibly open a little more on the narrow side of the coupling. If you can get side/side and top/bottom within

As for up/down, I don't know. I haven't done that process.

I think I found a good write-up on shaft alignment. I will see if I can find it and post.

Edited by DIE2SURF

Share this post


Link to post
Levi900RR

Good info man and great call on at least checking it so I know what the current status is. Thanks

Share this post


Link to post
DIE2SURF

and I certainly wouldn't balk at having dealers do it. Nothing like having a pro/experienced person handle weird/intricate work to make sure it's done right. Hopefully they won't charge you >$500.

Share this post


Link to post
Levi900RR

I was kind of thinking that would be my cut off. I mean they are $80 per hour and I have to think it's less than a 3 hour job for a pro. But anything less than $500 and I'd be satisfied.

Share this post


Link to post
Levi900RR

Ran out of time to do it the other day. I'm going to hold out a few more weeks until I pull the boat for the winter. Not worth missing even a few hours of water time this late in the season.

Share this post


Link to post
DIE2SURF

I found the instructions (paper) on this. I will scan and post for you as a potential resource. I will look in my Clymer's book as well. Might be something in there.

EDIT: here is one I've looked at to determine possible issues. http://ebasicpower.com/faq/alignib.htm

I still know I had a better description of the process...just need to find that one.

Edited by DIE2SURF

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...