Alpha 1 Gen 1 gear ratios

[ArtK]

I have a Alpha 1 Gen1 with the # OD463386 on the side of the upper 3 inches below the vent screw. There is no Gear Ratio number. It is a 22' 1992 Bayliner Ciera Series 2255 " sunbridge" 305cu. in. GM engine 175 hp. I have been told # OD463386 is a model 5010198CS with a 1.98:1 final gear ratio. Also been told all lower gear ratios were 1.62:1. I have counted the gear teeth in the upper a number of times and get 22 teeth on the driving gear, the shaft with the U-Joints, and 20 teeth on the vertical drive shaft for a 1.1:1 ratio.
1.62/1.1= a 1.47:1 final gear ratio. What am I missing here????

 

[kghost]

You just got the # 6 manual correct?

All the ratio info should be in the manual.

Also not all lowers are the same ratio. In many cases when an alpha is used on a larger and heavier boat the lower ratio can be 2:1

 

[kghost]

one other note, a1992 wiuld have a gen 2 dfive. 1989/90 was the end of gen 1 based on serial number.

 

[kghost]

You just got the # 6 manual correct?

All the ratio info should be in the manual.

Also not all lowers are the same ratio. In many cases when an alpha is used on a larger and heavier boat the lower ratio can be 2:1

Meant to say, Final ratio based on different lower ratio can be 2:1

 

[ArtK]

Meant to say, Final ratio based on different lower ratio can be 2:1

With the # OD463386 it is a 1990 unit, I have checked that out with Mercury dealers.
I cannot find anyplace in the manual that lists the 22 tooth drive gear and a 20 tooth driven gear.
I also cannot find in the manual a reference to lower gears that would give me the 1.98:1 final ratio.

 

[kghost]

 

[ArtK]

View attachment 33501

Thank you, What I think happen is the upper housing that has the # OD463386 on it is a replacement. I did 5 turns on the drive shaft to the lower and got just a tad over 3 turns on the prop shaft So with the 22& 20 gears on top and the 17 & 28 Gears in the lower it would be right about a 1.50:1 final . once again THANK YOU