High Pitched Squeall in slow forward

[Ben62]

Hi all hope someone can help. I have a 31 TE single Cummins. My drive shaft was recently shortened by 2 inches because you could not remove the prop without dropping the rudder. The shaft was re-keyed new cutlas bearing placed. Now after running the boat for about 30 mins, when I drop back into slow forward , I hear a high pitched squeal. Goes away in neutral. Out it back in gear, it returns. At higher rpm you don't hear it.
When it first started, you could only hear it in forward, now you can hear it in reverse.

Any ideas?

Thanks

Ben

[RobS]

Have you ruled out the belts? The fact that in/out of gear changes the noise could just be due to the slight rpm change. When you hear the squeal, spray the belts with belt dressing and see if the noise changes.

[jleonard]

The belt is a serpentine. If Rob's suggestion doesn't pan out, remove the belt (takes 10 seconds with a breaker bar) and check the idler pulley by hand to see if the bearing makes noise (a possible troublesome area of a Cummins 6BT).
I would look at the latest change for the cause....how is the cutlass bearing cooled? Is it a dripless? Is it stll getting water for lubrication? Does the shaft appear to run out of round?

[rcwhite]

Did you have or add a brush on the shaft? These can be quite noisy at low speed until they wear in.

[Ben62]

Thanks for all the help. Belts are ok. Cutlass bearing is dripless. Next step is to check the flow of the water from the motor to the bearing. Will let yall know

Ben

[jleonard]

Thanks for all the help. Belts are ok. Cutlass bearing is dripless. Next step is to check the flow of the water from the motor to the bearing. Will let yall know

Ben

The SHAFT SEAL is dripless, that's the correct terminology. The cutlass bearing needs water for lubrication. Two different parts and systemsof the boat.
It helps us to help you if we are all on the same page.

[RobS]

Do you know what dripless shaft seal is installed? Tides, PSS, Halyard, etc. If there is a component connected to the shaft that has come loose that could be the squeal, like a metal sleeve or collar that is supposed to be connected (fixed) to the shaft is now riding the shaft.

[Ben62]

Shaft seal is pumping as it should be. Boat was hauled and o e side of the cutlass bearing shows excessive wear. Yard thinks they iinstalled I correctly.

Will post update

Ben

[Russell]

This sounds like an alignment problem.

[Bill Foley]

I had the same issue last year after replacing the cutlass bearing, I have a dripless set up with no cooling, just the 1/2" holes on either side allowing water to run through. It quieted down after 20 hours or so of running. My guess is the set screws that hold the cutlass in place were over-tightened.

[Ben62]

Update.

Boat was hauled. I found out the cutlass bearing used was metric and too tight for the 2 inch shaft. It was wearing more on one side secondary to poor alignment. Bearing replaced and alignment fixed and problem resolved.

All costs covered by the yard.

Ben

[slimjim]

thats great news Ben. Enjoy the summer!