Strange Transmission Motion/Sound on Yanmar 3JH2-TBE

[geoffschultz]

I have a Yanmar 3JH2-TBE with a KM3A1 gear box. I was just spinning the prop shaft by hand and noted that as I spin it, it suddenly gets easy to spin and then I hear a clunk and then it gets harder to spin. The clunk seems to be coming from the transmission. This only happens if I spin it quickly and it occurs at random points in the rotation (it's not at the same angle) and it occurs in both directions of rotation.

I must admit that I've never tried spinning my prop shaft at the transmission coupler before, so I don't know if this is normal or not. Can anyone tell me what I'm feeling/hearing and if this is something to be concerned about?

-- Geoff

 

[geoffschultz]

Wow, 52 views of the topic and no answers. :cry: I'm getting the feeling this isn't common or most people don't try try this. At minimum, thanks for reading!

-- Geoff

 

[Neal4200]

Is the clunk the sound of your folding prop opening up, or do you have a fixed prop?

 

[geoffschultz]

Is the clunk the sound of your folding prop opening up, or do you have a fixed prop?

I have a MaxProp folding prop, but that isn't it. I can hear/feel this every time that rotate it 30 degrees. I would expect to feel it unfold once, not with each movement. I've play with it enough underwater to know how it reacts.

Thanks for the idea, but I'm afraid that it's in the transmission, as that's where the sound seems to be coming from.

-- Geoff