2003 Johnson ST 55 HP WRL 2 Stroke Commercial Service Manual, PN 5005483, Page 160Get this manual
MIDSECTION EXHAUST HOUSING
Installation
Place the exhaust housing in the swivel bracket assemblyApply Nut Lock to threads of the upper mount screwsInstall the screws and place ground lead under the center screwTighten the screws to torque of 18 to 20 ftIbs(25 to 27 Nm)
Install the lower mount bracket covers and screws