1978 Johnson 2HP outboards Service Manual, Page 15Get this manual
TUNE.UP PROCEDURE
When an owner brings motor to you for tune-up, or for some minor operating malfunction, the following procedure should be used as guide to determine the cause of the malfunctionWrite down the owner's commentsKeep an accurate card file on your service shop operationEach service operation should be on record as to the: OWNER'S NAME DATE MODEL NOSERIAL NONATURE OF COMPLAINT NATURE OF WORK PERFORMED COST TO THE OWNER WAS WORK PERFOMED UNDER WARRANTY? After writing down the owner's comments, check the motor visually and begin systematic tune-up procedureConsult the Trouble Check Chart to find the causes of any malfunction which may be discovered when tuning up the motor1
Remove exhaust cover and cylinder headSlowly rotate flywheel and visually inspect piston, rings, and cylinder for wear, freeness, and carbon deposits
lc: ;1NOTE
Piston ring condition should be determined before continuing tune-upGum and varnish deposits on rings or piston may be removed with an application of OMC Accessory Engine CleanerIf piston, cylinder, and rings are considered to be in satisfactory