Knocking lower unit.

[Norris]

I have a knocking noise lower unit. Yamaha 60 2004.
The noise is audible when engine running in neutral and also when in both forward and reverse.

 

[fitz73222]

Any metal chips, water, or burnt gearoil seen during inspection? How did you determine the noise is coming from the gearcase?

 

[racerone]

Sounds like it might be a broken tooth on a gear ( forward ) most likely.

 

[Norris]

Sounds like it might be a broken tooth on a gear ( forward ) most likely.

Thanks for that. I was thinking that or possibly a damaged water pump, the noise does sound more like metal on metal though.

 

[Norris]

Any metal chips, water, or burnt gearoil seen during inspection? How did you determine the noise is coming from the gearcase?

No metal chips, water, smoke etc.
lifted the engine out of the water and the sound clearly coming from the bottom leg. Engine runs well and again no smoke on start up.

 

[racerone]

A 2 stroke or 4 stroke ?

 

[R_P]

Did you drain the gear oil? Not the engine oil, but the gear case by the prop. Was there metal in there or did the oil that came out appear metallic in a bright light?

 

[Norris]

A 2 stroke or 4 stroke ?

4 stroke

 

[racerone]

Remove lower unit.----Start motor momentarily.----Listen for noise.

 

[Norris]

Did you drain the gear oil? Not the engine oil, but the gear case by the prop. Was there metal in there or did the oil that came out appear metallic in a bright light?

Haven’t drained the oil.

Remove lower unit.----Start motor momentarily.----Listen for noise.

will try this as either way lower unit has to come off I think

 

[racerone]

You have to start somewhere to find a path forward.

 

[Norris]

You have to start somewhere to find a path forward.

True. Thanks.