are mercruiser aplha drive upper gear sets the same as

[lime4x4]

Looking into swapping from a 86 mercruiser alpha drive to a 91 mercruiser alpha drive.Can the upper gear set from the 86 be swapped into the 91 drive?

 

[lowkee]

Re: are mercruiser aplha drive upper gear sets the same as

Depends on the serial # of each. In '91 the Alpha 1 became generation 2, but only part way into it, so there are Gen 1 and Gen 2 '91 outdrives in existance.

If the uppers look *exactly* the same, then I would say yes, as the bolt pattern on the Gen 2 is different and it is apparent upon visual inspection.

either way, comparing the serial #'s is the most sure way to determine compatibility.

 

[Bondo]

Re: are mercruiser aplha drive upper gear sets the same as

Ayuh,... If I'm not mistaken,...
An Upper gear set from a Gen.II can be successfully be loaded,+ properly shimmed into a Gen.I upper Case...
But,...
Gen.I gear sets just Won't fit into a Gen.II upper gear case....

I bounced this around with My outdrive guy awhile ago,....
(Dave is like Our friend Don, always by the book,+ factory parts)
Basically,... For All of what We now know of as the Alpha series of outdrives,...
Many of the Parts can be used in a gear case of it's own vintage, or an Earlier(Generally) gear case...
Depending of course on What parts your talking about,+ Which vintage of Gear Cases you're refering too...

 

[lime4x4]

Re: are mercruiser aplha drive upper gear sets the same as

I'm looking at using the following drive serial # 0D576782 from a 1991 boat. The upper gear set is a 1.98 ratio. I need a 1.50 ratio. I have an extra set of upper gears from my old 1986 alpha drive which are 1.50 ratio.So i'm just looking at changing the upper gear set on the 91 drive.

 

[lime4x4]

Re: are mercruiser aplha drive upper gear sets the same as

also according to this website the inner transom plate is the same for all models
http://bpi.ebasicpower.com/mm5/merc...Product_Code=MER44117A8&Category_Code=MER2GIM

 

[Bondo]

Re: are mercruiser aplha drive upper gear sets the same as

I need a 1.50 ratio. I have an extra set of upper gears from my old 1986 alpha drive which are 1.50 ratio.So i'm just looking at changing the upper gear set on the 91 drive.

Ayuh,.... I don't do serial #s,... Is it a Gen.II or Not,..??

And,... What's the Inner Transom Plate got to do with Upper gear case Gears,..??

 

[lime4x4]

Re: are mercruiser aplha drive upper gear sets the same as

well the top cover on the 91 is different then my 86 so i'm going to assume it's a gen 2. That privios post of mine belonged on another thread i started

 

[Bondo]

Re: are mercruiser aplha drive upper gear sets the same as

well the top cover on the 91 is different then my 86 so i'm going to assume it's a gen 2.

Ayuh,... The Big visual difference is where the upper meets the lower...

Gen.IIs have Bolts,.. Alpha 1s have Studs...

 

[lime4x4]

Re: are mercruiser aplha drive upper gear sets the same as

i have bolts

 

[Bondo]

Re: are mercruiser aplha drive upper gear sets the same as

Can the upper gear set from the 86 be swapped into the 91 drive?

Ayuh,... As noted above,.... Nope...

Gen.I gear sets just Won't fit into a Gen.II upper gear case....

 

[lime4x4]

Re: are mercruiser aplha drive upper gear sets the same as

this is what is confusing this site sells one gear set that fits 1970 to 1997

http://bpi.ebasicpower.com/c/MER4A/Gears,+Gear+Kits+&+Sets+for+Mercruiser