Mercruiser Bravo Vibration


Old 09-04-04, 04:26 PM
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Mercruiser Bravo Vibration

Help! I have a 7.4 mercruiser hooked to a Bravo 1 drive. I get a vibration when turning or when the drive is up. In other words whenever the u-joints are angled. I pulled the drive and checked the joints, no side to side or rotational play, not dry, caps are tight. I greased them up and put it back on. still vibrates. on the trailer with flush on it actually rattles. After greasing it got quiter for a while but came back. In a turn on the water you feel the vibration in your feet. Could these joints be bad and not show it? At 50 bucks apiece I want to make sure I am not missing something.
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Old 09-05-04, 07:51 PM
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Hello Rick. Welcome to the Boating, Sailing, PWC, GPS, & Navigation topic.

Any part or componet in rotation or motion that is out of balance or has worn tolerances and or clearances can cause such problems. Even the prop.

The trick is determining where that problem lies. Exact location and or part(s) often defies even the best of boat mechanics. If there is any doubts about the condition of the joints and or prop, replace them.

Standard practice used in many shops. High speed out of balance parts can cause other serious problems, risks, acidents and or injuries. Certainly not worth overlooking any possibility or potental parts when the risks are that critical.

The diy resident boat service & repair professionals will have additional helpful information, suggestions and advice. Check back on your question several times for additional replies.

Kindly use the reply button to add any additional information or questions, etc. to this thread. Using this method also moves the topic back up to the top of the daily list automatically.

Regards, Good Luck & Safe Boating.
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Old 09-06-04, 05:11 PM
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Thanks for the info. I am going to pull the drive again and probably replace the u-joints. The vibration is much worse on turns and when the drive is up. Could I possibly have damaged this from running the engine with the drive in the trailer position? Any other thoughts are welcome. Thanks
Old 09-08-04, 05:24 PM
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HEy Rick you took our the drive to inspect the u joints but did you check out the ginmble bearing.that will also give you the vibe you are talking about.
Old 09-09-04, 05:28 PM
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I was told the gimbal was replaced before I bought the boat. I had pulled the drive about a month ago to replace a shift cable and boot, found the alignment was pretty far off. I had to drop one side mount about 3/4 inch before my tool would engage the drive hub. I had about ten hours on it that way. Do you think that could have taken out the gimble? Yes the motor is now level, the one side was much higher on the mount threads then the other side.

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