OMC/Cobra - Rebuilt lower unit noise

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'89 4.3L -- Tore up the clutch mechanism in the lower unit early this season and had a new lower gearset installed.<br /><br />When I picked it up from the marina they pointed out that when the shifter is in neutral and the prop is manually spun there is an unusual soft grinding sound in the lower unit - sort of a "rattle".<br /><br />The tech. said he realized it doesn't seem right, but that several of the OMC's he's rebuilt have turned out like that, but they've all operated fine.<br /><br />I've now ran the boat for ~20 hrs and the noise hasn't changed any, and the drive has performed well.<br /><br />I've never heard a good running lower unit that is anything other than silky smooth when you spin the prop in neutral (actually it's one of those things I do when I'm boat shopping - kinda like kicking the tires on a car). Is this noise something I should keep an eye on, or is it just one of those "characteristic" things?

 

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Re: OMC/Cobra - Rebuilt lower unit noise

can you hear it when the boat runs in netural? does it do it with the drive trimed down also?