Vibration and noise

[SS182]

I have a 1993 Wellcraft. I recently had the boat tuned-up, the upper gears replaced, lower unit rebuilt with new bearings, and engine realigned. To get the engine aligned I had to have the engine mounts altered by grinding down the front lower nuts. I took it out Friday and noticed that in low RPM's, the boat vibrated and made a pinging noise from below the engine. Could it be the mounts or do you think it is something serious? Can I still take it out or should I dock it until solved? Thanks for any help or advice. Also the boat seems to be running slower.<br /><br />Kyle

 

[flashback]

Re: Vibration and noise

I would check the alignment again, and with another mechanic.... you should not have to grind down engine mounts to align the shaft. something is bad wrong.....sounds to me as if your mechanic is trying to create more work for himself, the next thing you know, you will be replacing couplers and gimbal bearings......

 

[f_inscreenname]

Re: Vibration and noise

SS; I feel for you. I had to pull my motor 4 times this spring before I got it right. I guess the first question is.... How easy did the outdrives shaft slide into the coupler? It should have went right in except for the last 1/2 inch. The last 1/2 inch is where the rubber rings on the drive shaft slide into the gimble ring. <br />How low are the RPM's? <br /> The "pinging sound". Is it low or a high pitched sound? In gear or out or both? <br />"Vibration" In gear,out or both. Different RPM's? <br />Does the motor look straight (level from side to side)? Does it lean to far forward? <br /> Is everything tight inside the bellhousing? Had a friend,his combo (302/merc) worked great for a month when one of the coupler bolts came lose. Sounded like he blew the motor till we pulled it apart.<br /> A 302/Mercruiser combo is not that hard to make work. Did three of them in the back yard (don't take it wrong I'm not trying to down you) but it still sounds like you have a alignment problem or a mechanic problem.<br /> One thing I would like to add is; When you have it apart again (if you do) When you used a alignment tool to line up the motor and before you bolt on the outdrive spin the motor a couple turns and try the alignment tool again to see if the coupler is bent. If it is problem solved. You could also check this by pulling the outdrive sticking the alignment in and having someone crank the motor to see if it wobbles. Just a thought.

 

[hondon]

Re: Vibration and noise

Grinding down anything to achieve proper alignment is not acceptable.Wellcraft is a reputable boatbuiler and I doubt that your motor mounts have sagged to the extreme that this hack has represented to you and if they had that tech should have let you know up front.What caused the need for this gearcase rebuild in the first place?

 

[f_inscreenname]

Re: Vibration and noise

A little help (that SS182 didn't tell us in this post) before you make a discussion on what's wrong. You should read the post "Engine Mounts". It is a continuing problem from that post. This is a true mystery if everything was done right. I am not sure it was though,wish I lived closer. I would have to check it out in person. Sure would like to figure it out for the guy. He has to much in it to bail out now. The same place I was about three months ago before I found out that Chrysler uses a pilot bearing in the motors crank end. A long story I wont go into here.

 

[SS182]

Re: Vibration and noise

Hey Everyone, <br />Thanks for all of the great replies. I took the boat out today and ran it for about 5 hrs. It seemed less pronounced today, made the noise only once and the vibrations were infrequent and hardly noticeable. However I do not want to ignore any signs of problems.<br />*Flashback-The alignment thought seems possible to me. I will have to get a "new" mechanic to check it out. Thanks.<br />*F_inscreename-You have been a lot of help, thanks. I wish you lived closer too! I do not know how easy the shaft went into the coupler, I will check with mechanic. The RPM's are about 3000 on take off(prior to gear replacement, low end performance was much better)Prop size ? but do know that it has a 21 pitch, 3 blade ss. 2000 RPM's tended to be a vibration point. Pinging sound was high pitched did it in Neutral and up to 1000 RPM's, it seemed like it was coming from the engine coupler area. The motor looks straight to me? I checked out the Drive shaft at different RPM's and it appears to be straight, no visible wobbling. I have not checked on the bellhousing, yet. <br />*Hondon-The last owner repowered from 4.3 V6 to 305 V8 and left the 1.98 gearing, the gears were chewed. It all started with a simple tune-up and before you knew it here we are! Thanks for your help. <br /><br />Thanks again,<br />Kyle

 

[Valv]

Re: Vibration and noise

If you want to find an inexpensive alignment tool, I bought on Ebay a new driveline shaft (only, no cv joints) for any mercruiser, I paid $ 15.00, paint lightly seating surfaces then slide in to gimbal bearing with motor installed. It should go in with not much force, and when you pull it out look at paint where it cleaned off, it'll give you a good hint how to align it.<br />I hate to spend $ 80 / $ 90 for an alignment tool, you can also have a friend with machine shop build it for you for few bucks, there was a post many months ago with the drawing.

 

[SS182]

Re: Vibration and noise

I took the boat out Sunday. The noise and vibrations seemed to be gone. Should I just let it go or keep investigating? <br /><br />Thanks for all of your replies,<br /><br />Kyle