2006 3.0 mercruiser constant clicking noise

[Jackson805]

So I have a 2006 3.0 mercruiser with a constant clicking noise at idle and with acceleration. It’s not coming from inside the engine as it’s too loud. It’s coming from the back of engine bay near motor mounts ( which are tight) and flywheel area. It’s not apparent at all listening around outboard. Clicking doesn’t change when I trim up or down or steer left or right. Motor starts n runs perfectly as it’s a new rebuild. Replaced alpha drive gaskets, greased splines, fresh gear oil, spun gimble bearing w finger and was smooth w no play. I’ve checked exhaust flapper and flexes properly. I have no idea where it’s coming from. Any ideas would be appreciated.

 

[makomark]

do the click increase their frequency of occurrence when the engine RPM is increased?

 

[Jackson805]

Yes

 

[Jackson805]

do the click increase their frequency of occurrence when the engine RPM is increased?

Yes, throttle up the clicking increases

 

[makomark]

You can pull the outdrive to isolate that as a source when briefly running the engine.

It is possible something has fallen into the flywheel cover and interfering with the flywheel...the newer USB cameras function as excellent inspection cameras for these types of situations....

 

[Dieter]

Agreed pull the drive and see if noise is gone First thought would be gimbal bearing or ujoints

 

[Jackson805]

Agreed pull the drive and see if noise is gone First thought would be gimbal bearing or ujoints

Ok will work on pulling drive today. If it was gimbal bearing or ujoints would it still consistently click in neutral at idle?

 

[Jackson805]

You can pull the outdrive to isolate that as a source when briefly running the engine.

It is possible something has fallen into the flywheel cover and interfering with the flywheel...the newer USB cameras function as excellent inspection cameras for these types of situations....

I have a bore scope I will use today great idea!

 

[Dieter]

Ok will work on pulling drive today. If it was gimbal bearing or ujoints would it still consistently click in neutral at idle?

Yes on an alpha drive the entire drive line from drive shaft coupler , entire drive except the prop shaft is moving when the engine is running.

On an alpha the prop shaft just gets locked in gear when not in neutral.

 

[Jackson805]

Yes on an alpha drive the entire drive line from drive shaft coupler , entire drive except the prop shaft is moving when the engine is running.

On an alpha the prop shaft just gets locked in gear when not in neutral.

Gotcha, appreciate the info.