97 Volvo Penta Vibration

[clownboy24]

Hey there. I have searched and read threads for an hour before posting this question. I cannot find this exact question and would love some help please. I have a 1997 Volvo Penta 5.7 with Cobra SX. Last Fall I test drove this boat and there was a major vibration while driving it. It was worse when turning, and I could trim it a little to find a spot that was not as bad as others. The repair guy said sounds like a gimbal bearing, no big deal. I bought the boat this Spring and had him put a new bearing in. He said old one was shot and u-joints look good. I have not had boat in the water or running since I bought it until yesterday in the garage with muffs. It idles fine and quiet. In neutral with outdrive up, when I rev it up there is a major vibration. My stomach hit the floor. After a day of worrying what went wrong and reading some posts, I tried it tonight with the outdrive down and it is smooth as butter. Why is this? Do I have a problem? I read starting your boat with the trim up is bad for the gimbal. True? Cant wait to get on the water, but worried things still are not right. Any input greatly appreciated.
Thanks.

 

[Bondo]

Re: 97 Volvo Penta Vibration

I read starting your boat with the trim up is bad for the gimbal. True?

Yes...

 

[171mach1]

Re: 97 Volvo Penta Vibration

NEVER rev the motor with the drive UP!!!!!!!!!! to much stress on the u joints.

 

[clownboy24]

Re: 97 Volvo Penta Vibration

Of all the posts I've read on this vibration, I have never read not to rev up in up position. Thanks for reading and replying. So now the question is would you get that vibration with the drive up with good ujoints? The mechanic said they looked good. I gave it maybe six quick bursts of throttle in the up position. And I mean quick(short). Do you think I need to worry about the ujoints, or put it in the water and start using it?

 

[Don S]

Re: 97 Volvo Penta Vibration

With it trimmed all the way up, the ujoints may hit the transom shield, which will destroy the transom shield. I would be pulling the drive and looking, along with checking the bellows for water and checking the ujoints.
You should NEVER start the engine when the drive is in the full up trailer position.
It may not say that in any manual, but the manual also doesn't say to hold the throttle wide open when in neutral.

 

[clownboy24]

Re: 97 Volvo Penta Vibration

Thanks Don. That is the noise and source of vibration. Hitting the transom shield. You nailed it. I will have to take off drive and see if the shield is damaged.
So you're nit supposed to rev wide open on the trailer? I kinda figured that being that I've owned a few motors in my day. Being a first time boat ownerhowever I can see I have a few things to learn about that aren't in the manual. ; ) Thanks for all the help. You guys are great.