Long Shaft -vs- Short Shaft

[ddrieck]

Hello Everyone,
I am looking to replace the damaged lower unit on my 1978 Merc 500 50.
My question is...How do I know if it is a long shaft or a short shaft. Does anybody have the measurements for each?

Thanks in Advance

 

[oregonboatnewb]

Re: Long Shaft -vs- Short Shaft

I've got a 1968 500 merc and 17in is short 20 1/2 is long, you need to drop lower unit and measure the drive shaft, then just match it up online, ebay has a few lowers right now.

 

[Chris1956]

Re: Long Shaft -vs- Short Shaft

Measure from the transom clamp to the antiventilation plate. 20 " is longshaft, 15" is shortshaft. You can also measure teh boat's transom height.

 

[ddrieck]

Re: Long Shaft -vs- Short Shaft

Just measured and mine is a long shaft. So, its off to ebay to look for a replacement. Thanks for the measurments

Darren