What is this noise?

[beatlebug7]

I recently had my stuffing box tightened slightly to stop a steady drizzle of water coming in (now it drips at a normal rate). However now there is a "wub wub" noise whenever the shaft is turned manually and when the engine is in gear it is a quite alarming sound and rattles everything. What's happening and how do I fix it??!!

[Shenandoah52]

Do you have access to the flanges that mate your propshaft flange to the trans flange? If you do and are mechanical you could remove the bolts holding that connection together and either by eyesight or by using a feeler gauge determine if those flanges mate concentrically. If they don't, you may have an engine alignment problem. By re-tightening the packing gland what was before an unnoticed alignment problem can now be seen because the tighter packing is now restricting the flex of the prop shaft. This could go away with time by self-loosening, so to speak, of the packing gland. But then you would be right back where you started.

Another thing you could check is to see is if the strut is not only secure to the bottom of the boat, but also that is it not cracked. I've had them crack parallel to the cutlass bearing and require replacement.

Basically, you would want to determine if an oscillation is occurring with the prop shaft caused by either misalignment issues or defective parts. Additionally, if you disconnect the propshaft flange from the trans flange you can isolate the vibration or noise and rule out anything forward of those components with the exception of aliment issues.

[model 10]

First thing would be to back the nut off.

[newhaul]

I would have to say that you likely have an alignment issue .

[Monte Cresto]

Noise and vibration sounds like a worn out cutless bearing problem. Had the same problem when I had a flexible shaft coupler.