MC-1 Gearbox

smellyfish

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Jan 20, 2021
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2
Evening all, I have a 1980 Aristocraft with a Mercruiser 3.0 140hp with a MC-1 Sterndrive. The gears in the gearbox are damaged and I need to replace them. Is there a kit out there that would give me the gears, bearings and seals that I'd need to rebuild it? Would anyone know a part number for a kit?
Thanks!
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,353
Sometimes when the gears go out they flare out to the point where they cut into the water jacket or you cannot get them out because of the groove that is cut into the case.
You are better off looking for a replacement either used or new from SEI.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Evening all, I have a 1980 Aristocraft with a Mercruiser 3.0 140hp with a MC-1 Sterndrive. The gears in the gearbox are damaged and I need to replace them. Is there a kit out there that would give me the gears, bearings and seals that I'd need to rebuild it? Would anyone know a part number for a kit?
Thanks!
The 'kit' is called a new SEI drive. It's cheaper to buy that than even just the parts for a re-build, and that doesn't even take into account the 8 special tools you'd need for shimming and setting gear heights and preloads, or the special shop tools, like a press, a handful of feeler gauges and a whole lot more I haven't even thought about in almost 2 decades). And if you haven't done the job before, it's going to be 'interesting' for you...

Way easier and cheaper to just order an SEI (with a 1.94:1 ratio) and wack that on. And you get a 3 year warranty!

Chris.....
 

Bondo

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Apr 17, 2002
Messages
71,204
Evening all, I have a 1980 Aristocraft with a Mercruiser 3.0 140hp with a MC-1 Sterndrive. The gears in the gearbox are damaged and I need to replace them. Is there a kit out there that would give me the gears, bearings and seals that I'd need to rebuild it? Would anyone know a part number for a kit?
Thanks!
Ayuh,...... Welcome Aboard,...... What they said, ^^^,......

Buy yerself an SEI Alpha 1 replacement drive, slap it on, 'n go boating,......

Btw,.... If yer MC-1 has the shorter input shaft('bout 8", vs: the Alpha's 9" shaft,) you'll need to swap that out on the new drive,.....
 

smellyfish

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Jan 20, 2021
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Ayuh,...... Welcome Aboard,...... What they said, ^^^,......

Buy yerself an SEI Alpha 1 replacement drive, slap it on, 'n go boating,......

Btw,.... If yer MC-1 has the shorter input shaft('bout 8", vs: the Alpha's 9" shaft,) you'll need to swap that out on the new drive,.....
I took yall's advice. I live near SE and am picking up my SE106 on Friday. Yes, I have the short shaft and they checked that first. It was in stock and warranty card will already be filed when I pick it up. I think that it would have cost me half of the price in parts to repair my old MC-1. Thanks for the input and it made my decision much easier!
 
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