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Where to find a new lower unit Alpha one

J

jrwoodward

New member
My boat has been setting for 2 years. I ruined my lower unit and I could use some assistance on making sure I get the right thing. I would love to find a used rebuilt lower unit.
What do I search for?

I have a 1988 Century 3500 with 5.7 motor. From what I can tell or read I think I have an Alpha one Gen one?

I'm a new boater, in fact I bought this 2 years ago and hit something on my 1 at trip out (bummer) and haven't touched it since .

I have a small shop and we can do most anything as long as we have detailed instructions. (Mostly work on Chevy 5.3 s and Ford 5.4 trucks)


When I go on eBay they start mentioning gear ratio and such. That's where I get lost. Any advice would be much appreciated.
 
1988 Alpha One Gen One

Gear ration for 350 V8 is typically 1.50:1

Your boat specs out as a 20-21 ft boat so 1.50:1 ration and ANY alpha one Gen one lower with that ratio will work.

If you find one and are not sure, Take some pictures of vertical drive shaft and water pump assembly and post.

Gen one's the Vertical shaft should only have splines, No o-ring groove. If it does that would be an MR (Pre Alpha one but functionally the same)
 
kghost said:
1988 Alpha One Gen One

Gear ration for 350 V8 is typically 1.50:1

Your boat specs out as a 20-21 ft boat so 1.50:1 ration and ANY alpha one Gen one lower with that ratio will work.

If you find one and are not sure, Take some pictures of vertical drive shaft and water pump assembly and post.

Gen one's the Vertical shaft should only have splines, No o-ring groove. If it does that would be an MR (Pre Alpha one but functionally the same)
Click to expand...

I forgot to add,

The upper gear case controls the gear ratio.

Most, NOT all lowers are a standard gear tooth configurations. If lower comes from a very large boat or high altitude it may be a different ratio.

That being said. Any Alpha one Gen one and MR lower should be acceptable to use.

Best thing for you to do to be sure is,

Make a mark on prop shaft, Make a mark on vertical drive shaft.
Rotate Vertical shaft one revolution and count revolutions of prop shaft.
What ever that result is, Make sure replacement is the same.
 
Exactly what did you hit? The drives are built to take a whack. Did you crack the housing? Even that isn't the end of the road for these if it's not too badly damaged.
If you just knocked the skeg off, that is repairable.
 
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