Lower unit compatability question

[109jb]

I need to either fix or replace the lower unit on my 1997 Mariner 115 hp outboard. I have located a lower unit from a 1998 90hp Mercury, but am trying to figure out if this lower unit will work on my Mariner. Does anyone know?

 

[109jb]

Re: Lower unit compatability question

Anyone?

 

[Faztbullet]

Re: Lower unit compatability question

Sorry as the 90hp will not work due to gear ratio and clutch dog(6 jaw) You need a lower unit from a 1987-1997 as they where 3 jaw units,if you use the 1998-2006 115 unit you will have to change the shift shaft as throw is different..

 

[109jb]

Re: Lower unit compatability question

Thanks. That bring up another question. The one I am looking at comes with the shift rod. It has is the rod that comes through the mid section and has the arm at the top. If I have this can I use the 98 lower-unit?

 

[109jb]

Re: Lower unit compatability question

No offense, but it looks like you are wrong. It took me a while to find out what I needed, but what I found in the online parts manual says the 1998 90 HP lower unit will work just fine on my 1997 115. Here is what I found.

In 1998 the 90 hp engine could have come with either a 3-jaw or 6 jaw clutch. The one off of this 90 is a 3 jaw just like my 1997 115 hp. It has the straight edge on the machined flat by the fin bolt just like my 115. BTW, according to the parts manual the 1997 115 could have also come with either a 3 jaw or 6 jaw clutch.

Again, looking at the parts manual, the 90 hp 3-jaw and 115 hp 3-jaw clutches both have the exact same part numbers for all of the gears (pinion, forward, and reverse). Since they have the same part numbers they have to have the same ratio.

Anyway, I looked at the unit and it looked great so I bought it.