1998 Johnson Evinrude "EC" 90, 115 SPL Service Manual, P/N 520209, Page 165Get this manual
Cleaning and Inspection 1Clean all parts with parts cleaning solvent and dry with compressed airAll nut and screw threads coated with CIVIC Screw Lock or CIVIC Nut Lock must be thoroughly cleaned before assemblyWhen using thread locking product, be sure to prime the threads with OMC Locquic Primer2Discard all seals, a-rings, and gaskets3Examine the upper and lower thrust mounts, and replace if deteriorated or damaged4Before checking the exhaust housing for distortionthoroughly clean the top and bottom mating surfaces and remove all sealer and corrosion
5Check the exhaust housing for distortionPlace the housing on surface plateUsing dial indicator, check flatness by measuring the run-out on the top edge of the housing The maximum allowable run-out is 0.009 in(0,228 mm)If you do not have access to dial indicator and surface plate, seek the services of machine shopDO NOT attempt to st raighten distorted housing; replace itDR2223