Funny noise

[wumhenry]

Originally Posted by soul searcher

I would think that if the problem were in your cutless bearings that when you are docking the boat and go into reverse with a little headway on that you would hear the same or close to the same sound.
just a thought

I don't. One more reason for looking elsewhere.

[deniseO30]

silly question.. have you checked the transmission for lubricant?

[timebandit]

Here we go---
Engine sounds normal------eliminated.
Engine mounts would make a clunk sound when shifting into gear under all conditions----eliminated.
Transmission under the same load in smooth and choppy water-----eliminated.
Transmission mounts would make a clunk when shifting in gear under all conditions----eliminated.
Drive shaft and bearings work the same in smooth and choppy waters-----eliminated.
Some kind of thrust bearing going bad should make noise all under all conditions in forward gear---eliminated.
Might try reverse in choppy water---would unload the thrust bearing.
You say the prop is ok and tight-----eliminated.
I doubt the hull is flexing and causing this noise or you would have noticed it before.
Still there is still one thing that might make a Clatter noise and is connected to the transom.
The exhaust system might have a loose clamp some where and is banging against something..

-----and the professor was killed in the parlor with the candle stick-----

Please let us know when you find out.

[wumhenry]

Originally Posted by deniseO30

silly question.. have you checked the transmission for lubricant?

Not since the beginning of the season. I'll have a look next time I go aboard.

Do you think a shortage of lube could cause a noise that's heard only when motoring in a chop?

[wumhenry]

Originally Posted by timebandit

Here we go---
Engine sounds normal------eliminated.
Engine mounts would make a clunk sound when shifting into gear under all conditions----eliminated.
Transmission under the same load in smooth and choppy water-----eliminated.
Transmission mounts would make a clunk when shifting in gear under all conditions----eliminated.
Drive shaft and bearings work the same in smooth and choppy waters-----eliminated.
Some kind of thrust bearing going bad should make noise all under all conditions in forward gear---eliminated.
Might try reverse in choppy water---would unload the thrust bearing.
You say the prop is ok and tight-----eliminated.
I doubt the hull is flexing and causing this noise or you would have noticed it before.
Still there is still one thing that might make a Clatter noise and is connected to the transom.
The exhaust system might have a loose clamp some where and is banging against something..

-----and the professor was killed in the parlor with the candle stick-----

Please let us know when you find out.

I said that the prop isn't fouled, but I haven't checked to see whether it's tight. If it were loose, could that cause the noise that I've described when the boat is motoring in a heavy chop and without causing it when the boat is motoring in flat water?

[wumhenry]

'Nother hypothesis: could the noise be caused by the zinc rubbing against the cutlass bearing due to hull flexing or a loose coupling?

[timebandit]

Assuming all the tests have been made with the exception of---
Reversing in choppy water.
A diver to check underwater stuff (prop-zinc-other).
We cannot dismiss the power train and move elsewhere.
Problems like these are a mechanics nightmare.
The ones that begin with "It only happens when---"
Oops!
I have forgotten two very important questions that should have been the FIRST ONES.
Is this boat new to you??
Have you motored under these conditions and had this problem, or is this the first time??

[wumhenry]

Originally Posted by timebandit

Assuming all the tests have been made with the exception of---
Reversing in choppy water.
A diver to check underwater stuff (prop-zinc-other).
We cannot dismiss the power train and move elsewhere.
Problems like these are a mechanics nightmare.
The ones that begin with "It only happens when---"
Oops!
I have forgotten two very important questions that should have been the FIRST ONES.
Is this boat new to you??
Have you motored under these conditions and had this problem, or is this the first time??

I bought it in July 2006. I got the same funny noise last year when motoring into a heavy chop.

[timebandit]

Any fix yet?