Howling noise in drive

[Donzi GT250]

I just had the u joints replaced on my 1989 5.7 cobra.
And yesterday after getting the boat back in the water after the u joint replacement I now have a howl coming from what sounds like the drive.
This howl starts abruptly at 850 rpm and seems to fade at around 1100 rpm.
I didn't have this howl before the u joint replacement and when I had the u joints replaced the mechanic said he checked the gimbal bearing and it was greased well and all was OK as he said it was dry in the bellows.
If I put the drive in neutral and run the engine in the rpm range that causes the howl it doesn't make the noise. So the noise is only when the drive is in gear.
Any ideas?

 

[Donzi GT250]

Re: Howling noise in drive

Yep just as I figured

 

[ljsweeney]

Re: Howling noise in drive

I would check that the new u-joints were properly lubricated.

You also said that the mechanic checked the gimbal bearing for grease - did he also use an alignment tool before reinstalling the outdrive?

I'm assuming that you've checked the level of gear lube in your outdrive. If not, take a look at that as well.

Good luck.

 

[bruceb58]

Re: Howling noise in drive

Second the checking the gear lube. Many don't know how to fill a Cobra properly.

 

[Donzi GT250]

Re: Howling noise in drive

Gear lube is good.

 

[Donzi GT250]

Re: Howling noise in drive

Well I think I found the culprit for the howling noise.
Today I swapped out my prop for a prop of the same make and model so essentially I swapped it out for an identical prop.
No more noise, go figure.