Alpha One Lower Unit Noise

[bukrose]

I have a Mercruiser alpha one gen 2 lower unit. It's making a dull knocking noise when I turn the vertical drive shaft. I don't hear it if I turn the prop shaft. Here's a video of what it sounds like...

https://youtu.be/qgrTbEfHZ5U

I'm not sure if this is a problem or not... Would love to hear from someone with experience here.

Thanks,
Bukrose

 

[Bt Doctur]

Try turning the unity upside down and I bet it disappears. The gears are cut to force the shaft upwards to set the gear clearance.You should also notice vertical play in the driveshaft
3B-60 and 3B-61 in here http://www.boatfix.com/merc/Servmanl/14/14b3.pdf

 

[Rick Stephens]

Sounds like the dogs are ticking. Put it in gear and turn the shaft clockwise and it should be gone. Bt Doc is the true expert. Just my 2?

 

[Pete104]

Stand it upright & give about 10lbs of force upwards on the driveshaft and try again. As BT stated.
The drive/gearcase isn't mean't to be on it's side either.

Just change the impeller and you'll be fine.

 

[bukrose]

Thanks guys. My gut told me it wasn't an issue, but it doesn't really know anything stern drives! I think I'll go with Pete104's last suggestion - because i'll probably drop it on my foot trying to turn it upside down... : )

-bukrose