On a Speedmaster #3 with 1.68:1 gears will the lower unit have the same ratio gears as a 1.5:1lower unit or is it a combination of upper and lower to acheive the the 1.68:1 ? .. I want to use a lower unit from a drive that is 1.68 and put it on a upper that is 1.5 :1 and achieve an outdrive that is 1.5:1 .
Mark

They either have 1.125 lower, or 1:1 lower. A 1.68 ratio, is a 1.5 upper, with a 1.125 lower. The only way to have 1.5, would be a set of 1:1 gears for the lower, or possibly if Gary RPMRAM on oso, who can get these gears made, might be able to set you up with a new set of 1.33 or 1.31 uppers, which would give you a 1.47 or 1.49. Not sure if he can do that on a reg 3 drive, but if anyone knows, he would.

I have two 1.5 drives L ,R one with a bad lower and know of a set of 1.68 drives with good lowers and a bad upper , so if i use both lowers of the from the 1.68 set on my good 1.5 uppers i will have a good set of 1.68's
Correct ? With 1.68 how would i prop the boat if it had say 26p 4 blades with the 1.5's
Mark

hey mark, give me a call I'll tell you how to check what you have... Alan 905-722-6684

I have new 1.31:1 net forged, straight cut upper gear sets for all the SSM drives. #3, #3A, #4(with internal polygon) and #5. I also can supply new LH and RH 1.125:1 lower gear sets for #3A and #5 drives. The 1.125:1 lower gear sets for the #3 and #4 have a different internal spline on the 2 pinion gears that attach to the 2 verticle shafts, than the lower gear sets for the #3A and #5 drives. Crazy, the only way you will be able to make a 1.5 ratio drive, from what you describe with your #3, is to just swap the 1.5 upper gear you now have and replace it with a 1.31:1 upper gear set that I can supply. Either call me (612-247-7081) or e-mail me at [email protected] and I would be happy to help you.

Gary will take care of you. He took care of getting all the gears i needed and even set me up with a good shop. I was impressed with the whole process.

Adk.......how do you tell what you have? I was told my drives are 1.33 but am really wondering what they really are?

If they are 1.33 how much would it cost to turn mine into 1.50's?

Thank you all for your help,
cheers!!
Mark