Converting a 1990 Mercury 9.9 to 15.

Discussion in 'Outboard Maintenance' started by MrMoser223, Mar 17, 2010.

  1. MrMoser223

    MrMoser223 Woah! Wait a second I didn't do it!

    I want more out of my motor without having to buy a new motor. So if someone is bored and wants to tell me the parts I need to do this conversion. Thanks guys.
  2. Flyline

    Flyline Won "Do More With Less" Award!

    Depend on year of the motor.

    I'm going to pick up mine. It's 05' mercury 9.9hp 2-stroke converted to 18hp by swap bigger carb, exaust tuner, and reeds. It's aint cheap to do it.

    U can find a used parts like 15hp carb and maybe a reed plate or exaust tuner. So I don't know about yours.

    If I were you...sell your 9.9hp and look for 15hp 2-stroke.

    Converted from 9.9hp to 15hp plus is really expensive. It's about 600 bucks to do it.

  3. Peter2006

    Peter2006 I Love!

    Carb is Identical part number but the 9.9 and 15 pistons and block are different. Must be the porting, because new replacement pistons are the same number.