Why two serial numbers?

[WA2DGQ]

I have a MerCruiser 5.7L (circa 1990) with an Alpha Gen 1 drive.
Engine S/N 0C867508; Transom S/N: 0D330502; Drive S/N 0D324109. Anyone know why the ?Transom? has one serial number and the ?Drive? has a different S/N number? The schedule of parts listings (MerCruiser Parts Express website) obtainable under each of the two serial numbers appears to be identical and incorporates exactly the same parts, part numbers, schematics, etc. Every part (and part number) shown under one serial number is replicated under the other number. Therefore how is the definition of ?transom? as used here different from the definition of ?drive?? What components make up a ?transom? while what components constitute a ?drive?? MerCrusier appears to consider the two terms synonymous. I could find no one at either the MerCruiser Stillwater or Fond du Lac customer services centers that could explain this in any way that made sense.

 

[cr2k]

Re: Why two serial numbers?

Transom numbers is for the transom bracket. The part that bolts thru the transom that the drive and the engine both attach to.

they are numbered to track any changes in design over time.

 

[zbnutcase]

Re: Why two serial numbers?

And because the drives are sold seperatly. When you buy complete power package the engine, drive and transom plate are pulled out of stock randomly,then crated. 'nutcase

 

[WA2DGQ]

Re: Why two serial numbers?

Thanks to both of you for that info. Unfortunately, I am still confused. I fully understand that we have three separate serial numbers correlating to three separate entities, the entities being the engine, the transom mount and the drive. However if the transom serial number is for the transom bracket alone then one would think that when one enters the transom bracket serial number into the parts catalog that only those components unique to the transom bracket would be listed under the transom serial number. What I am finding is that when I put the transom serial number into the search box, all the DRIVE components come up as well under the serial number for the transom mount. How can each therefore be random and unique when there is this overlap?

 

[zbnutcase]

Re: Why two serial numbers?

Because there are serial number RANGES of drives and transom plates used together; entering the transom plate serial will also include the drive serial ranges used with that transom plate. Confusing? Maybe, but it allows the parts cat to be devided into 2 parts ( engine, and outdrive) instead of three. And since parts are looked up by the DRIVE serial, I imagine the transom plate is serialed for theft reasons more than anything. 'nutcase

 

[WA2DGQ]

Re: Why two serial numbers?

Thanks again guys. I think I may be beginning to see the light here. I thought back on how Yamaha does it. On my ?94 jet ski when I look up parts under the ski?s HIN, I find that many part numbers have changed over the years for what appear to be the same components on the schematics. Yamaha tells me they change part numbers because they are tracking various changes in the parts such as improvements, sourcing from a new manufacturer, making the part more universal, etc. It is rather confusing for the Yamaha parts buyer since they are faced with a bunch of crossover numbers. Perhaps Mercruiser is doing something similar here only using a different approach. It seems like Merc is taking an important part here like the transom bracket and giving it its own serial number so they can track changes, etc. Bottom line is I guess I shouldn?t be concerned about this process. When I want a particular part I should simply look it up under BOTH transom and drive serial numbers. As long as it is the same part number, on the same schematic, for both serial numbers I?m home free. (As has been the case so far.) If there were a difference, I would simply need to call Merc and have the apparent discrepancy resolved. The problem I have with Merc all along is that after calling two different service centers in their two primarily locations (Stillwater and Fond du Lac) NO ONE that they put on the phone at either location seems to understand the process and/or is able to explain it.
Merc?s processes are probably fine, they just need more knowledgeable reps to explain them.

 

[Bondo]

Re: Why two serial numbers?

When I want a particular part I should simply look it up under BOTH transom and drive serial numbers.

Nope,.. If you need a part of the transom assembley, use It's serial #...
If you need a part for the Drive,... Use It's serial #....
Just because a Picture in the parts look up show Both the transom assembley,+ the Drive is pretty much irrevelant...

Many, Many times the Outdrive is Not the original to the hull, or motor, or transom assembley...

Personally,...
I see nothing wrong with the system, only because so many boats no longer have the Original units on them...