Gearbox serial

hmmm.. once again 20918 isn't showing as a gearbox serial number...

typo?

No, I am looking at the picture and it definitely has S/N 20918 stamped on it. It is just the gearbox so I don’t have an engine serial number.

I suspect that gearbox  comes from an engine that was too old to look up (predates the electronic serial number database...)

Gearbox PN 888560 decodes as follows...

Version 2 Gearbox.
*** WithOut Clutch. ***
2.43: 1 Gears.
Wide Dog-Gears.

S/N 20918 is way older than S/N 34903.
Also, remember that the Main reduction Gears are a matched set.
If you do not have the matching Crankcase gear for the 20918 Gearbox, you will need to transfer the Prop Shaft Gear to maintain the pairing.

- - -

Can/Should you use the older gearbox to replace the newer one?  WHY???
Either Gearbox should be inspected/refurbished before re-installation.
Why is the Older box not installed on an engine?  What happened?  How long has it been out of service?
What is wrong with the current Gearbox?  Why do you want to replace it?
What is the story going on here?

Hi all

Bill is correct, this is a very old box your looking at.  The housing is a sand cast  version and was replaced a long time ago.  You can tell the sand cast version with the large cast in boss where they stamp the serials.  The newer versions are made from a permanent mold and the serials are parallel with the prop flange (new versions are lighter and machined for the wide gearets for better clearance) Technically they function the same however the newer case has better machining in my opinion.  

Cheers