1989 Cobra on 4.3 liter engine makes a funny noise

[rolmops]

While testing my engine I heard a funny noise coming like something rattling from in or around the outer unit. It sounds like a loose piece of metal banging against something. It is not bothering the engine or lower unit performance (as yet) and when I engage the gear it goes away. For now I will dig up my stethoscope and see If I can more precisely locate the source of this noise What could it be and what should I pull apart?

 

[Mc Tool]

Ooooh ! that sounds expensive . I would start looking at either the motor or the drive unit .

 

[rolmops]

I used the stethoscope to pinpoint where the noise is from and it is neither in the engine , nor in the lower unit or gear housing. So far , that is good news.
I'm hoping , maybe a loose screw or something that fell down when attaching the lower unit. The funny thing is that the noise is gone .