1994 Sea Ray Sundancer 270 How To Find Ratio Of Bravo 3 Lower Unit?

[jws123]

The time has come for me to start working on my new to me boat. It is a 1994 Sea Ray Sundancer 270 with a 7.4 and bravo 3 drive 350 hours. The guy I got the boat from did not take care of the drive by any means the lower unit is basically swiss cheese badly corroded he never kept up wit the paint on the drive even the trim rams are shot. I found a decent non corroded lower unit but what i need to know is how do I find the ratio of lower unit? there are no numbers anywhere left on the drive case.

Thanks.

 

[altitude 411]

It will most likely be 1.81, 2.00 or 2.20 to 1

pull the drive and turn the yoke 20 turns and have someone count prop revolution ( place blue tape on one of the blades)

20 revs of the yoke equal exactly 10 revs of prop =2.00

22 turns of the yoke for 10 turns of the prop = 2.20

18 ( 18.1) turns yoke for 10 prop= 1.81

edit... check for 2.00:1 first save time and divide by 10 ie) 2 revs of yolk 1 turn of prop = 2.00 : 1

 

[jws123]

It will most likely be 1.81, 2.00 or 2.20 to 1

pull the drive and turn the yoke 20 turns and have someone count prop revolution ( place blue tape on one of the blades)

20 revs of the yoke equal exactly 10 revs of prop =2.00

22 turns of the yoke for 10 turns of the prop = 2.20

18 ( 18.1) turns yoke for 10 prop= 1.81

edit... check for 2.00:1 first save time and divide by 10 ie) 2 revs of yolk 1 turn of prop = 2.00 : 1

ok thanks

 

[jws123]

Picked up good used lower unit today but having problem finding new Orings to re join upper/lower unit every time I try to look it up i only find whole seal kits for lower unit ?