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Mercruiser 74l bad vibration

S

smc

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I have a 2001 mercruiser 7.4l

I have a 2001 mercruiser 7.4l w/ a bravo 1 out drive. It has a bad vibration on sharp turns and when you trim it up. I replaced the engine coupler with a new one and replaced the gimbal bearing. The u-joints are fine I also sent the prop out to be checked and it’s fine. The prop shaft is not bent. This all started after I hit something in the water. If you have any suggestions please let me know. Thank you!!
 
If it started after hitting so

If it started after hitting something you would think prop except it's been checked and if it was the prop it would vibrate when going straight too. The only thing that changes when you turn or trim is the angle of the u-joints. How do you know the u-joints are ok? How old are they? hours? I had a knocking noise and slight vibration when turning at low speed. I pulled the outdrive and could not feel any play in the u-joints but replaced them anyway and that took care of the problem.
 
Is the vivration from the stee

Is the vivration from the steering or the back of the boat as in outdrive?

How do you know the prop shaft is NOT bent?

When you replaced the coupler and gimbal did you check alignment?
 
We put a dial indicator on it

We put a dial indicator on it and checked the prop shaft and we checked the alignment when we put it back in. the vibration is from the back of the boat.
 
The u-joints felt tight but we

The u-joints felt tight but we did not replace them. it has about 200 hours on it.
 
If the ujoints were not loose

If the ujoints were not loose as a goose then I would suspect that first. Easy enough to check.

They should be very very loose with no real drag.

The shaft should flop all over the place when handling it.
 
"Did you check the rest of the

"Did you check the rest of the 'pivot points' on the outdrive to make sure nothing got pulled loose? If any of them have slop, it will shake.

Coupler fastened properly and with new hardware? if its loose, that can do it, too."
 
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Yes every thing else seems fin

Yes every thing else seems fine. We installed a new coupler and went by the specs in the book. We are a marina and our guy’s are certified. But they just can’t seem to find this problem. Mercruiser told the one mechanic it would self align in about 5 hours. That does not sound right to me.
 
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