Lower Unit Noise-Engine OFF

[billwright43]

1985 Merc Alpha One Lower unit. With the engine off, sitting in the yard...I spun the prop and hear a slight amount of noise like gears meshing but not grinding. The prop spins freely and I haven't had trouble on the water. Just wondering if I'm supposed to hear anything when I spin the prop like this? Also, when I grab the prop and pull it fore and aft it has a slight bit of travel...maybe 1/16 inch. Are these things normal or is something wearing out?

 

[Don S]

Re: Lower Unit Noise-Engine OFF

The fore and aft movement is normal, the noise is not. It's probably due to the shift cable adjustment. It is probably not completely into neutral and the shift dogs will just touch and cause a clicking sound when you turn the prop.

 

[billwright43]

Re: Lower Unit Noise-Engine OFF

The fore and aft movement is normal, the noise is not. It's probably due to the shift cable adjustment. It is probably not completely into neutral and the shift dogs will just touch and cause a clicking sound when you turn the prop.

 

[billwright43]

Re: Lower Unit Noise-Engine OFF

Sorry about the blub where I requoted you Don. I appreciate your response.
Sounds like you are onto something. Last time I had the boat out, I did notice it would not always falling into neutral when I wanted it to. I'd Jiggle the forward/reverse throttle and it would go into neutral. After reading your post, I went outside and cranked and shifted the lower unit several times trying to make sure it was in neutral so that I could spin the prop and see if I still hear that meshing gear noise(it's not loud or scary sounding-but it's there).
Once time today in the yard I got it to where when I spun the prop in one direction it was silent but made the noise when I spun it in the other direction.
Don't know if the following is related to the above but it may be....I've noticed that when I put it in reverse I hear gears slightly grinding before it falls into reverse. Kind of like an old manual shift car when the clutch isn't in enough.....like it's just slightly out of sync. Maybe it didn't go fully into neutral before I tried to put it in reverse????
How do you adjust that throttle cable or lubricate it or can you?

 

[Don S]

Re: Lower Unit Noise-Engine OFF

It's not the throttle cable you need to worry about, it's the lower shift cable that needs adjusting. Most likely it needs replacing. They are a cheaply built cable, and don't last forever.
Here is a link to a free, online, OEM Mercruiser manual.

http://www.boatfix.com/merc/Servmanl/6/6covr3.pdf

Check section 1-C, starting on page 1C-38 is a discription on how to adjust the cable. Usually when a cable goes out of adjustment, it means the cable needs replaced.