Quick Point of clarification on engine part

[jsakat1]

Quick point of clarification. On the outboard motor what is the lower mount? Is that the lower unit? I am looking to buy a replacement outboard a 90 merc and it says it needs the lower mount replaced. If some of you could help a rookie out...appreciated.

[GoneFission]

The lower unit is the assembly on the bottom of the motor that includes the gear casing, water pump and pickup, and the driveshaft up into the engine.  The next level up is a basically hollow part called the midsection, then up to the powerhead.  Mercury 90 HP lower units look like this:

 

You can expect to pay $300-$600 for a used lower unit in good shape.  Don't even think about what a new one costs...  

Good luck!