Mercruiser bravo noise in drive??

[Lukelona]

Noise now coming from outdrive/driveshaft area.
Took it out for the first time and noticed grinding knocking sound from drive to engine area.
Never heard nose like this so not sure what to check
This video shows it on the trailer

PLEASE DONT DELETE MY POST AGAIN?? I didn't do anything wrong with last post and after spending all the time to post, it got deleted by guest immediately??

 

[Lukelona]

In water noise, started in N and sounds fine part way through you'll hear it put in gear and get louder. This is part throttle

 

[Bt Doctur]

U joint or gimbal bearing I would not run it untill fixed plus the rpm`s are way too high on a hose

 

[Bt Doctur]

Might have happened because of "Guest"?

 

[Lukelona]

U joint or gimbal bearing I would not run it untill fixed plus the rpm`s are way too high on a hose

The hose demonstration was in gear idled up. It idles alot lower.
I'd honestly LOVE for it to be a gimbal bearing or ujoints. I'm so worried it's in the drive or coupler.i can't afford them repairs right now!
I don't think it could be anything I did when I just had the drive off, it's kinda a only goes together one way type deal right? I'll be removing drive again today after work and I guess I'll put joints and a bearing in.
Just have to find a puller I can use for bearing.


Is there a joint part number that can be bought at auto parts storevfor the bravo outdrive?
I did that with my alpha and got Spicer joints for 1/4 of the price.

 

[Lukelona]

Ok, pulled the drive off again on my lunch break.
There seems to be a little water in the ujoints Bellow but the Bellow isn't torn or loose.
I'm thinking the oring that seals the outdrive between gimbal and outdrive must be leaking?
Anyway, as far as the noise, the bearing was kinda stuck in place until I spun it then it was free. It wasn't like locked up tight, but obviously has issues. When spinning it by hand it is pretty smooth, makes a little noise. I am gonna replace it, but I don't think it's the noise I was having.

I started engine without the drive and reved it up like before and I swear it almost sounds like it's making the noise still but not nearly as bad.
I'm suspecting engine coupler may be making some noise. I've never experienced that though so idk if it's even possible.
The ujoints don't have any binding, and rotate smoothly. Appears they've been replaced at some point. I can't see how they'd be making any noise.

I wanna puke just thinking about having to pull motor for engine coupler. Seeing as I just got this dang boat and would like to use it lol gotta do what ya gotta do I guess.

Any input appreciated! I'm not sure where to go from here..

 

[Lukelona]

I installed new gimbal bearing and outdrive seals. I greased the ujoints bc they don't seem to be bad at all. No binding or play.
Ran it again with drive off, it definitely making noise still I'm pretty sure. Kinda hard to tell bc it's so loud from exhaust.
I guess I'll install drive and retest in water tomorrow. If it still doing it I guess I'll be pulling motor to inspect coupler. Idk what else to do.

 

[Lukelona]

Any ideas guys and gals? I'm lost here. Trying to reinstall the drive after work and just back the trailer in water at ramp and see if it still making that noise.

 

[Lukelona]

My local merc dealer says couplers don't make noise when they get worn. They either work or they don't.
As in slipping...

 

[alldodge]

Agree, couplers do not make noise with the drive off, unless the bolts are loose. If they are loose you should see it wobble looking thru the gimbal bearing hole. Could even take a rod and stick in thru the gimbal hole (with motor off) and see if it moves.

If its not the gimbal it may be the flywheel or even a rod knocking.

 

[Lukelona]

its not a rod knock, I am a certified dealership tech so I know the engine is good shape.

​UPDATE- I can not get the drive to go all the way back in after replacing gimbal bearing.
​it goes until about 1-2" then stops. after a few attempts I looked at drive shaft and it appears
​like it is hitting gimbal bearing at the top but doesn't look like its hitting on bottom.
​So I'm thinking the alignment may be off now but I don't have a tool. I'm going to try and find
one to rent or borrow.

The weird part is I just had the drive off a couple days ago to fix shift cable and it went right back
​in that day. Only thing I can think is since I had the drive off longer and the motor settled?

​I did reach down and wiggle the coupler to see if it had any play and it doesn't seem to.

 

[H20Rat]

The hose demonstration was in gear idled up. It idles alot lower.

Hard to tell exact rpm's on that clip, but you never want to be much above idle on the hose, doesn't matter if if it is in gear or not. Your water pump will pump more water than the hose can supply if you have decent rpm behind it. Probably won't damage it, but certainly not recommended.

Anyway, I was going to say rod knock listening to the second clip, but sounds like you ruled that out. This is going to sound painfully obvious, but did you double check your spark plug cables? One cylinder missing on a v8 at idle can make a sound like that.

 

[Lukelona]

Hard to tell exact rpm's on that clip, but you never want to be much above idle on the hose, doesn't matter if if it is in gear or not. Your water pump will pump more water than the hose can supply if you have decent rpm behind it. Probably won't damage it, but certainly not recommended.

Anyway, I was going to say rod knock listening to the second clip, but sounds like you ruled that out. This is going to sound painfully obvious, but did you double check your spark plug cables? One cylinder missing on a v8 at idle can make a sound like that.

It wasn't idled up very high. Just above idle. But only ran it for less than a min at a time anyway.
I haven't gave it a tune up yet, it actually runs great so I was trying to work out the bugs first then I'll go through maintenance items.
Oddly the video makes it sound a little different tone and a little louder than it really is.

Could the motor mounts be worn enough that the engine vibration is just running through the hull and outdrive? Idk I'm really at a loss on this one.
I can't get this dang outdrive back mounted to be able to retest with the new gimbal bearing to see if that helped. Only thing I know really that can stop the drive from going in would be the alignment right?

 

[alldodge]

A new gimbal bearing is very stiff, in most cases if its not perfectly centered it will be hard to get the drive back on. To center it the tool is inserted and then smacked all around with your hand until the tool goes in. Always good to check alignment after work or removal. Don't see the mounts just giving out after the drive is off. Try to get a better look at the coupler, I'm thinking there is the issue. Maybe bump the starter and see if things change

 

[Lukelona]

A new gimbal bearing is very stiff, in most cases if its not perfectly centered it will be hard to get the drive back on. To center it the tool is inserted and then smacked all around with your hand until the tool goes in. Always good to check alignment after work or removal. Don't see the mounts just giving out after the drive is off. Try to get a better look at the coupler, I'm thinking there is the issue. Maybe bump the starter and see if things change

Ok. This is the first gimbal bearing I've done. I've done most everything except that and a engine coupler.
It's obviously hard to inspect the coupler as it's buried on back of engine... But what should I look for on it?:
I need to get a damn alignment tool. Nobody will rent me one ugh. Guess we won't be out this weekend again. .

 

[alldodge]

it appears ​like it is hitting gimbal bearing at the top but doesn't look like its hitting on bottom

But what should I look for on it?:

If (the big IF) the drive is aligned but the gimbal is not centered, you should be able to tip the gimbal bearing down slightly (Hitting on top, not on the bottom). It you do this and the drive slides in you should be good.

Basically the alignment tool is used to center the bearing to the coupler at first. Once centered its used to check how far off it is

 

[Lukelona]

I got the drive on earlier. It was hard but went on. I'm going to buy a alignment tool online and take it back off. I really just wanted to test it at the ramp to see if it was still making noise.
Well....it is. Now I'm actually wondering if it is the motor knocking. I greased ujoints and coupler when it was apart. It still make noise
What I do t get is it only makes the noise when it's in the water. It doesn't do it on the hose. I'm assuming it's bc of the strain put on it when in water.
I put my hand on coupler and top of drive and don't feel anything.
Gna have to go back to ramp with stethoscope and check engine.
If so I'll be selling it bc I can't afford an engine right now

 

[Arrgh]

So what did you eventually find?

 

[GA_Boater]

So what did you eventually find?

He's been gone for 3 years, so we'll never know.

Closed.