Alpha One Gen 2 - Can I change gear ratio from 1.47 - 1.62 ?

s50cam

Recruit
Joined
Sep 8, 2017
Messages
2
Hi,

I have a 2005 Ebbtide 2100 with a 5.7 350 Mag. Unfortunately it developed a fault which we've now identified as the U joint failing, the shorter shaft part literally sheared off and there is some damage to the upper case gears. It appears to have run too hot / dry as the nylon on the end of the joint has melted.

From advice received so far I have three options -

- Upper case rebuild, new u joint, gears etc
- Buy an aftermarket upper case such as the sterndrive SE116
- OEM new uppercase

My preference is the OEM route but I literally cant find any deals on one of these, its coming in at $2000 USD plus fitting
A rebuild is going to be about $1500 USD or a SE116 is $1300 (I'm in the UK so dearer than USA)

However local to me there is a company which has a brand new upper case, its old stock and I could have it for $1100 BUT its a 1.62 ratio not a 1.47

I've been told all the lower case's are the same so it should 'fit' but will I have any problems etc, is it a good idea ?

I'm guessing I would need to change the prop after, its currently got a 21 degree but even with this included it would be much cheaper than a new OEM

Any advice would be really appreciated, I've seen there are some really experienced members on here.

Thanks,

Cameron
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,306
you can re-gear the upper. talk them down to $850 and pick up a set of geats

what ever you do, after your back on the water, follow the PM schedule in the service manual. that included annual removal of the drive for inspection
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,468
Ayuh,.... Welcome Aboard,..... If yer runnin' a 21" prop with the 1.47:1 drive,...

I doubt you can buy a prop big enough to run the 1.62:1 drive on that hull,.....
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Easy way to find the required new prop... new ratio divided by old ratio times current prop size equal (pretty close) new prop size. So, 1.62/1.47*21=23.14. You'd only need to go to a 23" prop. Not sure what you're currently running (as to the style of prop), but 23" is a common enough size. Here's a quick list I got from the Merc prop site.... All these are 23" props, and include a part number if you need it. :D
Props.png


As for fitment, not a problem. All the different ratio drives use the same housing. The only difference, literally, is the gears inside.

Chris........
 
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