Offshoreracr

Can anyone tell me the upper & lower gear ratios it takes to make a 1.62 final ratio? A freind has the service manual but cannot find it and I can't remeber. I hate CRS!

Roger 1

Are you sure that you don't mean 1.68:1? I have the manual in front of me and it show that to obtain a 1.68:1 final that you need a 1.50:1 upper and a 1.125:1 lower. I don't see a 1.62:1 listed.

Roger

Zoomnfun

1 62 are in my drives

Roger 1

Ah ha! I just checked the supplement to the service manual and there it is. Upper raito of 1.44:1 and a lower ratio of 1.125:1 will give you the 1.62:1 that you are looking for.
This comes from the supplement for 3As. The 1.68:1 info came from the manual for 3s. I don't know if there is a difference in available ratios between the two or not.

Roger

Zoomnfun

works great on a heavy boat spinning a big prop, I get 60 at 3500 and 70 at 4000 in moderate water

Offshoreracr

Thanks for the help. I think the 3 & 3A use the same upper gear but I am not sure. Does anyone have an #3 upper gear set for sale. Mine have not broken but one set is getting pretty worn.

Comanche3Six

Here is a new upper set at a savings $1500
Mercruiser part #43-818658A1


http://www.mercruiserparts.com/partsByNumber.asp

Offshoreracr

The gears in my drives are straight cut not helical cut, at least that is what I was told.

Comanche3Six

The gears I posted are for a 3A SSM

Offshoreracr

Can't you get the gear sets in both styles?