Mercury 9.8 lower unit interchangability

[Scott Danforth]

I found a deal too good to pass up on a short shaft lower to turn my long-shaft electric start into a short shaft. The electric start is a 1984 and runs great. The complete lower (from exhaust plate down to prop) is from a 1973 based on the serial number.

I plan on researching tonight when I get home, however thought I would ask here if the 1973 short shaft lower would simply "bolt on" to the 1984 power head

Anyone from the BTDT crowd?

 

[Chinewalker]

I can't think of any reason off hand why it wouldn't work. Might need the support pan that the lower cowling rests on to make all the shift and throttle bits line up properly, but the exhaust housing on down should be good enough. Only issue I could think might crop up is the '73 has an o-ring at the top of the driveshaft, while I THINK the '84 has a seal in the lower part of the crankshaft. May or may not be an issue, but it is a difference none-the-less.

 

[Scott Danforth]

Thanks Chinewalker. any idea of a site that still has the parts listed for both the 73 (serial number 3612854) and 84 (serial number at home)

the mercury parts catalog says contact your dealer

I think I can still get a break down at crowley marine

 

[Mi duckdown]

The first thing I would is drop the lower units on both motors to see if the driveshaft splines are the same also. Plus I'm not quite sure when merc change from carbon steel shafts to SS

 

[Scott Danforth]

I just found out that the 76 and older shafts are not stainless. since the motor will see salt water. Im going to have to pass.