Merc 5.7 / Alpha 1; Can someone tell me what I actually have!! ?

[dlighttx]

1993 Model Year/Actually built 1992 Cobalt 206. Outdrive has been replaced; I can't find any information that looks to match-up. Engine S/N OD818702; Transom S/N OD757641; Drive S/N OW547500. Drive says Ratio is 2:00. When I try to look up parts, nothing matches up with what I actually have. Guess this is because outdrive has been replaced. Would this 2:00 drive ratio be the right one behind this engine? Thanks for any/all help understanding what I've actually got!

 

[Bt Doctur]

Drive # comes back as a Alpha GEN II 2.00-1, Engine 5.7 350Mag. The gears would have had to have been changed to run it with a 5.7

 

[Fun Times]

The drive serial number makes it out to be somewhere in between 2004-07 roughly. Here is your parts to the drive.

http://www.crowleymarine.com/search_results.html?string=0W547500

Inside that link, just input your other serial numbers for parts look up. Be sure to use a 0 (zero) and not an O..............


MERCRUISER ALPHA TRANSOM (ALPHA H.P. (1992) Serial No: 0D757641 Model No: 6010000ES Catalog No: 90-81818391...........




MERCRUISER W/ PS ALPHA I (5.7L H.P. (1992) Serial No: 0D818702 Model No: 457B100ES Catalog No: 90-816596

 

[dlighttx]

OK. Thanks, but now I'm even a little more confused. Its runs great & does just fine. I'm extremely happy with its performance. There's mention that a gear change would have been required to run it on a 5.7. How can I tell if my engine is 5.7 or 350Mag w/o using carb cover identifier?

 

[Bt Doctur]

there should be a metal plate on the engine boss just above the starter

 

[NHGuy]

If you want to confirm the drive ratio it's kind of a pain but turn the motor over in gear with someone watching the propeller. 5.7 motors usually have a 1.5 ratio drive behind them. When the propeller has turned 1 revolution the motor theoretically will have turned 1.5. Or if you really have a 2.0 ratio the motor will do 2 revolutions for each prop turn.
Look at the propeller for size and pitch information. Usually the diameter is first, something in the 14.25 to 14.75 is typical. The convention is to list pitch second. That should be some value in the 20's, normally odd inches like 21, 23, or if yours really is a 2.0 drive the pitch could be higher. If the boat has a 1.5 drive the pitch should be lower such as 21, 19 or 17".