[jmanng]

Hi Everyone:

The drive shaft on our 1991 Mercury 9.9 outboard snapped this past weekend. Took it apart and it measures 25".

I've been looking online and the parts diagrams provides several choices with descriptions of long, short or extra long... no where can I find how to determine which version we have (the clymer service manual doesn't say anything either). I'm baffled that the part selection wouldn't be a simple matter of quoting the overall shaft length (and diameter if required)? Am I missing something?

I would be grateful if someone could clarify what short, long and extra long mean?

Thank You,

Jaime
Oshawa, Ontario
Canada

[wscaman]

When I purchased my 2010 15 ProKicker I got this information. I did buy the 25" Extra long unit.


25" is extra long
20" is Long
15" is Short

[jmanng]

thanks for the info.

I also found another thread that was discussing this (don't know why I didn't find it earlier - outside of the mercury forum), anyhow reference diagram shows where to measure: http://www.iboats.com/ref/shaft_length.html

Still astonished that they wouldn't quote overall shaft length.

[emckelvy]

The length of the Driveshaft is not the determiner for Shaft Length of a motor. The Transom Height is what tells you whether a motor is SS, LS, or XLS.

Measured from where the motor sits on the transom, to the anti-ventilation plate on the lower unit. This is the Shaft Length.

If your driveshaft measures 25" from end-to-end, it's physically impossible for your motor to be an XLS.

I'd suspect it's more likely a Long Shaft motor. The extra 5" of length on that driveshaft is what's sticking into the lower unit and doesn't count in the measurement.

Measure the Transom Height of your motor and I expect that's what you'll find.

HTH.......ed