vibration from prop???
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=14448
Printed Date: November-17-2024 at 8:47pm
Topic: vibration from prop???
Posted By: newoldboat
Subject: vibration from prop???
Date Posted: July-14-2009 at 1:19am
|
Please help. I finally got my boat in the water this weekend and it has a vibration under acceleration and at speeds of 10mph and up. This boat had the same vibration when I test drove three months ago but I was hoping it was shaft alignment. I am 99 percent sure the shaft is aligned properly so I am thinking the vibration is in the prop or shaft. I know eyeballing is never accurate but the shaft looks straight. I have a spare oj prop with the same pitch from another project that I want to try before I spend all that time pulling the shaft. The million dollar question is can I get the prop off with the rudder still in? I have three jaw pullers but none will fit with the rudder in the way. I don't stand a chance of getting the prop off without a puller, it is on there pretty good. Every thing looks good to the naked eye, the shaft looks straight and the prop doesn't have any dings from impact. Is it possible for a prop to go that far out of balance without any impact? I did notice that the prop on the boat is very sharp on the leading edges and the oj spare I have is much thicker on the edges of the blades. I am wondering if this is an original prop that is worn out and out of balance. The vibration is enough to make the windshield shake at 20-25 mph. Any advise would be greatly appreciated.
|
Replies:
Posted By: 62 wood
Date Posted: July-14-2009 at 1:39am
Joe,
Im assuming you just bought the boat a few months ago? Has it ever been smoth since you owned it? Do you know if the prop you have on has been changed? The old one could have been tagged and replaced. What kind of prop is on it now? Its very possible a single blade could be off pitch.
If you have a spare prop, I would try that first, but you will almost need a prop puller to do it right. If your going to mess with these boats, you will need one someday anyway. Changing the prop would be a quick and easy first step.
As for the shaft, it really needs to be checked for runout, it would be awful hard to see if its slightly bent, but enough to cause a vibration. What does the cutless bearing look like/is it worn?
-------------
http://www.correctcraftfan.com/diaries/details.asp?ID=1117&sort=&pagenum=6" rel="nofollow - 64 American Skier
62 Classic..
73 Ski Nautique
|
Posted By: 8122pbrainard
Date Posted: July-14-2009 at 9:28am
When you did you alignment, did you follow the proceedure to check for a bent shaft forward of the strut? (It's spelled out in Eric's alignment thread)
You do not need to pull the shaft to check if it's straight. You will need a dial indicator clamped to the strut. On the prop taper will check if the shaft is bent aft of the strut.
-------------
/diaries/details.asp?ID=1622" rel="nofollow -
54 Atom
/diaries/details.asp?ID=2179" rel="nofollow - 77 Tique
64 X55 Dunphy
Keep it original, Pete
<
|
Posted By: eric lavine
Date Posted: July-14-2009 at 9:32am
Pete. goin early, stayin late to finish up these prop pullers....always last minute, but dammit we will meet on friday
-------------
"the things you own will start to own you"
|
Posted By: BuffaloBFN
Date Posted: July-14-2009 at 9:49am
I had a prop that was so slightly bent that it could only be seen on the workbench. Same with the shaft. I rolled it on a machined table and couldn't see any problem. I replaced it anyway and now it's smooth.
-------------
http://correctcraftfan.com/diaries/details.asp?ID=2331&sort=&pagenum=12&yrstart=1986&yrend=1990" rel="nofollow - 1988 BFN-sold
"It's a Livin' Thing...What a Terrible Thing to Lose" ELO
|
Posted By: 8122pbrainard
Date Posted: July-14-2009 at 10:05am
Eric,
I'm looking forward to Friday!! It will be a pleasure to meet.
-------------
/diaries/details.asp?ID=1622" rel="nofollow -
54 Atom
/diaries/details.asp?ID=2179" rel="nofollow - 77 Tique
64 X55 Dunphy
Keep it original, Pete
<
|
Posted By: eric lavine
Date Posted: July-14-2009 at 11:02am
feelings are mutual, but not lets talk about boats lol
-------------
"the things you own will start to own you"
|
Posted By: newoldboat
Date Posted: July-14-2009 at 3:36pm
|
Steve, yes I just bought this boat in march and have been redoing the stringers since. The only time I drove it was during the test drive and it vibrated then too. I have no idea what brand of prop is on the boat. The po said he had to have a new shaft installed so I am hoping maybe he reused a bad prop. I have an oj prop I am going to try this weekend if I can get the old one off.
|
Posted By: kapla
Date Posted: July-14-2009 at 8:20pm
Man if the windshield shaked as you state I would look again at the shaft aft the strut and the propeller... mine did shake like that after hitting the river bottom, prop had no ding as the bottom was mud, but hard enough to bend the blade and the shaft... Had to return towed as the vibration was tremendous when trying to take off...It was aligned one month before this happened and the prop was also 2 weeks old...
I had all straightened again and then it ran very very smooth....
The prop should go away with no problem even with the rudder. Or unless your shaft its longer making the prop to be closer to the rudder...post a pics to see.
I use to redneck remove the prop with the wood chisels and rubber mallet method, I learned that ain´t the right way so I was planning on buying a bearing remover like the one u have.. I think It won´t be good... So I´ll fabricate one... No prop removers here....or if you get one they charge almost $150....Eric do you still have those pullers? Can you mail it to Buenos Aires Argentina?
-------------
<a href="">1992 ski nautique
|
Posted By: rogier
Date Posted: July-19-2009 at 7:25am
Hi Joe,
I had exactly the same thing here. Changed the prop in the water (with the rudder on) and now it's completely smooth. Shaft alignment was not needed in my case.
With previous boats I've had waterbearings break (strut) and even worse by driving fast with an off-balance prop, so I would make this a top priority or not go fast enough to make it shake.
Good luck
|
Posted By: newoldboat
Date Posted: July-19-2009 at 10:07pm
|
I was able to swap props, the old one was a federal prop and I swapped an oj prop on. The boat still vibrates but it seems different. It vibrates badly under hard acceleration and gets really bad when I turn the boat with any throttle. I also noticed that when I put it in reverse and give it a little throttle it seems to chatter. This got me thinking that it could be the strut bearings. I removed the prop and shaft from the boat and I am still unsure of the cause. The shaft seems straight as an arrow but the finish looks bad where it rides in the strut. It is very shiny and has pit marks in the finish. Pulling the shaft out I noticed that it was kind of loose in the bearing but the bearing doesn't look worn. I am not 100 percent sure that the prop I swapped on is good. I got this prop from someone else and have never had it on a boat. I also noticed that the rudder is pretty loose in it's housing. Could the rudder be shaking around and causing the vibration? Anyone have a suggestion?
|
Posted By: newoldboat
Date Posted: July-19-2009 at 10:30pm
|
I can't find Eric's thread on alignment. Where should I look to find it?
|
Posted By: gun-driver
Date Posted: July-20-2009 at 1:50am
Here
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=6037&title=alignment - http://www.correctcraftfan.com/forum/forum_posts.asp?TID=6037&title=alignment
|
|