Outdrive gear ratio.

Retiredsdier

Cadet
Joined
Sep 4, 2022
Messages
7
Good afternoon everyone.
I'm Randy and I'm having issues finding the gear ratio on my upper unit. S/n 0D646810. That is off the transom gimbal unit. I would appreciate any assistance any one can give.
 

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Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
9,048
Is your stern drive a bravo 1 or 2?

What engine size/model?
 

Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
9,048
Probably going to be 1:50:1 but with the size of the boat it could be the 1:65:1.
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@Yegboats , Any chances of taking a peek to see if the transom 0D646810 is registered to a stern drive?
 

04fxdwgi25

Chief Petty Officer
Joined
Mar 25, 2022
Messages
537
My last boat was a Chapparal 2550 SX Sport w/ 7.4 and B1 drive and same weight as yours at around 5080 lbs dry and an 82 gal gas tank.. That was a 1.5:1 ratio and would run 53 mph all day long. I'll see if I can find the old prop size spec it had.
 
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Yegboats

Chief Petty Officer
Joined
Feb 20, 2016
Messages
518
Probably going to be 1:50:1 but with the size of the boat it could be the 1:65:1.
View attachment 401835


@Yegboats , Any chances of taking a peek to see if the transom 0D646810 is registered to a stern drive?
Unfortunately the transom serial # isn't registred. Any chance you have the engine drive, or engine serial numbers?
TRN: 0D646810 6020000ES MERCRUISER BRAVO I/II
 

Retiredsdier

Cadet
Joined
Sep 4, 2022
Messages
7
Unfortunately the transom serial # isn't registred. Any chance you have the engine drive, or engine serial numbers?
TRN: 0D646810 6020000ES MERCRUISER BRAVO I/II
Not at the moment. The boat is at a storage facility and I'm going there to do some work on it Sunday.
 
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