dna

I just picked up this boat last year, near end of season so really just now getting familiar with everything. One thing I noticed this spring when I first launched it is very noticable vibration in the middle of the boat when the leg is up. If I start to lower the leg it gets considerably less, but even when fully down I still fell the vibration under the steering area or anywhere near that. It is so noticable that you would think I have some sort of prop or something in the middle of the boat. I do not recall feeling that last year.

I know the description is vague, but any ideas? The engine runs smooth, and boat goes good in the water. No grinding noises coming from anywhere in the leg or engine area?

Thanks

mike tkach

the u joints in the drive input shaft might need to be replaced.

dna

Any easy way to confirm? If that is the issue what is next if I leave it? Is it a diy job? Thx

CDShack

Sounds like you already did the test. Generally the vibration on trim or hard side to side turns stems from the U-joints. That's not saying something else may have gone south because of or caused the bad U-joints, but the general idea is they are the problem at hand. Was it just a U-joint, did a bellows crack, stuff like that can be assessed as you look closer or take the drive off.

You can get u-joint "kits" all over, Ebay isn't too bad. Has all the gaskets, orings, et. you need to pull the upper box and get at the U-joints. Not a big deal but it does take some grunt and specialized knowledge to get it off and on. Check on YouTube, there is a wealth of instructional videos there. U-joints are Spicer, and can get them at OReillys. Tell them its U-joints for a 70 model Nova (no one there has any idea of what you'd ask for otherwise!)

vindicator101

Like was mentioned in one of your other threads when you asked where to set your drive when pulling off the trailer and maneuvering around the dock, putting the boat in gear when the drive is all the way up is a killer of u-joints. Seems like your seeing the effect of that now.

Griff

Lesson #1 would be: Your boat has an outdrive not a leg.

Do not run the engine with the outdrive trimmed way up. That ruins U joints and it does not matter if its in fwd, rev or neutral.

dna

I actually never posted that I do that, however coincidently I do. I kind of have to, cause the water is very shallow at my dock (~2.5 feet). Having the leg down would certainly damage the prop or the leg. When I do come to my dock, I go very slow.

Other than using oars, what other options would I have?

Sydwayz

It will absolutely vibrate when you have it trimmed up like that. It only trims up that high so you can trailer it without dragging the ground.

1) You could have it dredged.
2) You could row it.
3) You could walk it in.

Eventually, you are going to damage your U-joint as such that it will likely blow apart when you are up on plane, drive down, and at high RPMs.
That could literally rip the drive off the back of the boat and potentially have you taking on water. You know the rest of the story. That doesn't always happen, but it has happened.

dna

You definitely got me to change my habits. Gonna walk it in and out from now on. 2 questions. Can someone provide me the model of the ujoint I need to buy for a bravo1 or are there various ones? Other than the ujoint do I need anything else for the swap (ie gaskets)? I also have been looking on youtube for instructional video snd can't find a good one. Does anyone have good instructions?

Second, if the vibration is not that bad is it safe to keep using boat for a few more outings or is this serious enough that I sjould do immediately? Thanks

Brad Zastrow

No service the drive soon. Never start or run the engine with drive trimmed more than halfway up. Even in neutral the u-joints are turning. Have them change the bellows at the same time. These parts are not expensive and the does not take a long time to fix.