Gear Ratio
 

I recently purchased a used Teague Platinum drive from with a refurbished case, the seller thought the gear ratio was 1.36. After testing it on my boat, I have the ratio might be lower ... 1.26. Does anyone know how to determine the gear ratio on a drive ?

Count how many turns on the input shaft will turn the prop shaft 10 times and divide that number by 10.

15 turns give 10 prop turns = 1.5
13.6 turns give 10 prop turns = 1.36
12.6 turns gives 10 prop turns = 1.26

Thanks for your formula