Bravo Three vibration after removal

Mauro Brisola

Seaman Apprentice
Joined
Jun 13, 2016
Messages
31
350 MAG suffered Bravoits. With 150 salt water hours. A "experienced" Mercruiser mechanic did the work to solve overheat problem.

I did not followed the work because I live far from the marina where boat is.

What I know is outdrive was removed and engine raised in order to gain access to transom.

Overheat issue is past. Now engine temperature is about 158-160.

But there is new problem obviously related to the service that was performed: with low trim engine operation is smoth. No matter engine speed.

But trying, when cruising, to adjust trim to about "4" in the Mercruiser trim gauge scale (middle is 5) it starts a abnormal vibration, Not a terrible vibration but strong enough to shake and starting make some noise. Before this service boat was perfect. No vibrations in this situation at all.

Now problem starts because mechanic first reaction is to claim it was a pre existing-problems... What is not true.

My doubt: considering the removal and installation of outdrive what the most probable vibration cause in this case?

Thank you
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
First fixing this can be done with motor installed, but just more difficult.

When motor was reinstalled, was the engine alignment checked? If not this could be the cause. When a motor comes out it must have alignment checked

But trying, when cruising, to adjust trim to about "4" in the Mercruiser trim gauge scale (middle is 5)

This comment is abstract, because need to know if the trim limit was set, or rest correctly?
How do you know it is 4 inches out? Did you stop and measure how far the drive extended?
 
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