1974 Johnson 135 HP Outboard Motors Service manual, Page 15Get this manual
2-7 Install upper plug before removing lubricant filler hose from lower holeLower plug can then be installed without oHlossIf filler type can is not available, install lower plugSlowly fill gearcase through upper hole, allowing trapped air to escapeInstall plugSee "Lubrication Chart," Item 6 NOTE
Piston ring condition should be determined before continuing tune-upGum and varnish deposits on rings or pistons may be removed with an application of OMC Accessory Engine CleanerIf pistons and rings are considered to be in
satisfactory condition for continued service, remove carbon, surface and reinstall covers, using new gaskets
Recheck gearcase oil level after motor test has been completed2Clean carbon from cylinder head and top of piStonsReplace upper bearing crankshaft sealSur face and reinstall cylinder head, USing new gasket