fastfred252

I have a bravo one outdrive and i was hearing a bad noise when the boat was on plane. i had the drive checked and there was nothing wrong. it is a weird clunking noise. could it possibly be the gimball bearings?, which was changed 3 years ago. it spins just fine. what else could it be. i have thru-hull exhaust and it is hard to determine where the noise is coming from. engine is running fine although i put in 89 octane gas by accident. could that be the noise. PLEASE HELP!!!

FOUNTAINATLAST

Every time I've heard a clunking noise under plane its been my drive. When they checked it what did they do??? Did they pull it apart and inspect the upper gear set??? In the past I feel the clunk in the floor boards like someone knockin underneath the boat.

CMG

is it when fully trimmed??

fastfred252

yes

fastfred252

i had the guy check the upper gears and everything was good.he also said the lower is good.Could it be the gimbel bearing??

fastfred252

Its pissing me off i cant figure it out.

Anymore sugestions?
Thanks guys

CMG

u-joint on the way out? when trimmed up more pressure on it.

Mr Gadgets

Fred,
You have to be more descriptive of the noise.. tell us about your boat. Motor etc. 89 octane is not good for motor that needs 93. But that would be pre-ignition, death rattle. So I dont think that would be the cause.

When does it do it? Coming on plane, acceleration, WOT? Fully trimmed, ok. Does it do it all the time or only under WOT?? Tell us more. Standard Bravo? Any changes to drive and motor, or is it all stock? Do you feel it or just hear it??

If the guy looked into the drive, he should have looked at the ujoints. If they feel free, they are probably good.
The gimble bearing usually gives off a growl at low speed when they start to detorate.. my experience, not to say they cant clunk..
Could be loose bolts on the coupler or maybe a cracked couple plate. What style do you have.. Black hub sticking out of bellhousing with rubber donunt in it? There are thick ones and thin ones I believe, you may have a crack if it is the thin one and causing the clunk..

Can you make it happen and have the hatch open, maybe use a wooden dowel to touch things that might transfer noise so you can locate it.. You put the wooden dowel to your ear.. but becareful not to get near any moving parts..

Give us some more info.. and we will see if we can help.. but be patient..

hope this helps
Dick

fastfred252

ok heres the story.It ended up not being the drive it was my motor mount.it caused the drive to be unbalanced.I was so releaved that that was the problem so i wen and bought a new motor mount.

fastfred252

ok heres the story.It ended up not being the drive it was my motor mount.it caused the drive to be unbalanced.I was so releaved that that was the problem so i wen and bought a new motor mount.
My mechanic puts it in and the boat got put back in the water.
Took it for a testdrive and it still made the noise
now its like the a diferent noise its coming from the motor!
So i take the sparkplug out and there shot,So i figured its the gas...I got 93 and docked it.Then i went to the marine store and got new sparkplugs...Put those in and then went from another drive.
When i was out there i heard a bad noise
I open the hatch to hear it and its a very loud knock noise,so i give it a little gas and BOOM!
i blew the motor


*i have a 502 big block with a bravoI drive*
(massive work done to it)