Mercruiser Pre Alpha MC-1 Whine

kyddvicous13

Seaman Apprentice
Joined
Oct 16, 2011
Messages
36
Hey everyone, I've been working on my Grady with a 79 470, and pre alpha MC-1 out drive for the last 6 months. Finally got it where I was confident enough to water test it today. While I had it out the out drive started to whine. Never did it until I put it in the water. It only does it in gear, and it has fresh oil, and impeller. Any ideas??
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Mercruiser Pre Alpha MC-1 Whine

Only doing it in gear is no surprise, that when the load is on. At what speeds (engine rpm) is the noise? High pitched or low pitched? Does it change with engine speed? Have you had the drive open for any reason? What oil are you using?

Chris........
(and it's an MC-1 drive, not a pre-alpha MC-1....)
 

kyddvicous13

Seaman Apprentice
Joined
Oct 16, 2011
Messages
36
Re: Mercruiser Pre Alpha MC-1 Whine

Low pitched, from idle on up. I had it open to replace impeller and housing. Upper unit out to do the drive gasketand shift cable. Quicksilver lower unit oil.
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
70,986
Re: Mercruiser Pre Alpha MC-1 Whine

Ayuh,... Probably bad gear lash, or a bearin' on it's way out, or a gear with rusty teeth, or,....

Was there metal in the old oil, drained out,..??

Run 'er til she Pukes, 'n then buy an SEI to throw on it....
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Mercruiser Pre Alpha MC-1 Whine

Probably nothing wrong with it at all. Some do whine fairly loud. I owned one. Pulled that thing apart a couple of times trying to quiet it down, but everything checked out perfect. Ran it for 5 years with no problems at all, ended up selling it and the guy that bought it ran it for several more years before he moved and took it with him.
 

kyddvicous13

Seaman Apprentice
Joined
Oct 16, 2011
Messages
36
Re: Mercruiser Pre Alpha MC-1 Whine

No shavings and I've changed the oil 3 times. Popped the cap to look at the gears and check oil for water everything seemed to be in good shape none of the teeth were broken anyway.
 

kyddvicous13

Seaman Apprentice
Joined
Oct 16, 2011
Messages
36
Re: Mercruiser Pre Alpha MC-1 Whine

That's what has me torn Don I watched every vid I could find with a 470 and pre alpha. The alpha ones are quiet and the pre alphas seem to have that whine to them.
 

26aftcab454

Lieutenant Commander
Joined
May 12, 2009
Messages
1,510
Re: Mercruiser Pre Alpha MC-1 Whine

The MC-1 on my boat(Frisco Boater's Glastron) has the same whine-- It whinned when he had it -still wines today!
I may need an SEI unit someday but plan on good maitenance and run it till it pukes!
 

kyddvicous13

Seaman Apprentice
Joined
Oct 16, 2011
Messages
36
Re: Mercruiser Pre Alpha MC-1 Whine

I have an update on the drive, unfortunately not a good one. The drive started to whine while in neutral and gets louder with higher rpms. More of a high pitch to it now too. I replaced the gimbal bearing and greased everything again, but it seems to be getting progressively worse. The shaft was much tighter in the new gimbal bearing so im really dreading pulling this thing off. Any ideas or advice would be much appreciated
 
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