How to find the gear ratio

[mastercylinder63]

Greetings, I have twin 1997 4.3ltr mercruiser motors with Alfa1 genII outdrives. the port side has a crack in the outdrive case, so I need to replace it. I'm not sure which gear ratio I have. Any help would be great, Thanks.

 

[Bondo]

Re: How to find the gear ratio

Greetings, I have twin 1997 4.3ltr mercruiser motors with Alfa1 genII outdrives. the port side has a crack in the outdrive case, so I need to replace it. I'm not sure which gear ratio I have. Any help would be great, Thanks.

Ayuh,.... You can pull the drive, 'n rotate it manually, countin' the turns, 'n mathematically calculate it,...

Or,...

Pull the top cap, 'n count the teeth on the 2 top gears,...
With the tooth count, go to the Adults Only section, 'n dig up the Merc info that'll tell ya what tooth count is what gear ratio,...

I would Guess it's either the 1.84:1, or the 1.65:1,...

 

[Capt Ken]

Re: How to find the gear ratio

If its just the lower then don't worry about the ratio being they are all the same. The ratio gearing is in the upper. Now the kink , is it the counter-roatating engine?

 

[mastercylinder63]

Re: How to find the gear ratio

Thanks for the info. Of course it's the upper portion that's cracked. The "Plate Zinc Anode tab area" is what cracked off the upper portion of the drive during Superstorm Sandy. I don't think that an aluminum plate can be heliarced since it's a cast piece.

 

[longstand]

Re: How to find the gear ratio

Just wanted to say sorry for your lost regarding upper portion of your Outdrives.. Damm superstorm.. :laugh::facepalm:

 

[tazrig]

Re: How to find the gear ratio

If its just the lower then don't worry about the ratio being they are all the same. The ratio gearing is in the upper. Now the kink , is it the counter-roatating engine?

Wouldn't the port drive automatically be the counter rotating one?