1977 Evinrude 4HP Outboards Service Manual, PN 5303, Page 51Get this manual
EXHAUST
Figure 5-15Checking Ring Gap
Figure 5-17Correct Piston POSition bApply coat of oil to wrist pin, making sure surface is cleanPlace drop or two of oil in each pin hole in the pistoncInsert wrist pin through slip fit side of pistonOil wrist pin bearing in connecting rodPlace connecting rod in position, then proceed to install the wrist pinThis can be accomplished more easily if the piston is heated slightly, causing it to expand
Figure 5-16Checking Ring Groove Clearance
REASSEMBLY OF POWER HEAD
Proceed slowlyMake no forced assemblies unless press fits are called for, and make no "dry" assembliesBe sure all parts to be assembled are clean and free from dirt and gritPerfectly good cylinder walls, pistons, and rings can be ruined in few minutes of operation unless all forms of grit are removed before assemblyWork in clean surroundings and with reasunably clean handsCoat all bearing surfaces, cylinder walls, etc with clean oil before assemblyWhen the use of "oil" is specified, we recommend OMC outboard lubricant