Alpha 1 Gen 2 drive ratio?

[Simoniz]

Im sure this has been asked / answered before, but Ive had a look and cant see an answer to my specific question.
What is the drive ratio in my Alpha 1 Gen 2 drive, coupled to a 3.0l Mercruiser engine?
Year 2000, Engine No OL634881, cant find the drive No, is it stamped on somewhere?

 

[dubs283]

Factory should have been 2.00/1.98

If nothing has changed can verify by the letter stamped into the splined input shaft and cross reference with a chart in the manual. Otherwise you can remove the top cap and count the drive/driven gear teeth

 

[Simoniz]

Thanks. The drive shaft has 'A' stamped on it, and since Ive just had the drive apart, both top gears have 24 teeth.

Ive found @Bondo's tables in the Adults Only section, and it seems there's 2 possible combinations for the A1G2 drive, either 1.62:1 or 2.00:1 for the gears both to have 24 teeth.

I guess it depends on the gears in the lower unit. I don't want to rotate it too much to try it, as the impeller is new, and I cant remember if I assembled it with just some water, or used some rubber grease, but I guess I could just do 1 complete rotation of the input shaft. If the ratio is 2:1, then the propellor shaft will turn exactly 1/2 turn, if its 1.62 it will turn further, maybe 40 deg more.

 

[Scott Danforth]

3.0 gets a 2:1 drive
4.3 gets a 1.84:1
5.0 gets a 1.62:1
5.7 gets a 1.47:1

you dont have enough motor with a 3.0 to spin a 1.62:1 drive

 

[Bondo]

Thanks. The drive shaft has 'A' stamped on it, and since Ive just had the drive apart, both top gears have 24 teeth.

Ive found @Bondo's tables in the Adults Only section, and it seems there's 2 possible combinations for the A1G2 drive, either 1.62:1 or 2.00:1 for the gears both to have 24 teeth.

I guess it depends on the gears in the lower unit. I don't want to rotate it too much to try it, as the impeller is new, and I cant remember if I assembled it with just some water, or used some rubber grease, but I guess I could just do 1 complete rotation of the input shaft. If the ratio is 2:1, then the propellor shaft will turn exactly 1/2 turn, if its 1.62 it will turn further, maybe 40 deg more.

Ayuh,..... Just to expand on Scott's post, the 3.0l uses the 1.98/ 2.00:1 ratio,...
The 4.3l uses the 1.84:1 in a heavy hull, or a 1.65:1 in a light hull,.....
The 5.0l uses the 1.65:1 in a heavier hull, or a 1.5:1 in a light hull,.....
The 5.7l most usually gets the 1.5:1 ratio,...

 

[04fxdwgi25]

18' Bayliner I had years ago had a 3.0 in it with the 1.98 drive in it. Factory stock.

Just sayin'

 

[Simoniz]

Thanks all. I checked my lower unit this morning, just for interest, as I didn't doubt any of the pros on here for a moment. 1 rotation of the drive shaft made 1/2 rotation of the prop shaft, therefore 1:2.00 / 1:1.98.